dev-lang/rust: Set RPATH instead of using ld.so.conf for libs

For a reason lost to the sands of time, Gentoo was previously
disabling the `rpath` option in the Rust config.toml and instead
adding Rust the Rust lib path to `ld.so.conf` via entries installed
in `/etc/env.d`.

This was fine before we enabled slotting on the Rust package, however
with increasing numbers of Rust slots a hash collision was inevitable
and eventually happened between 1.84.0 and 1.84.1, resulting in
`undefined symbol` errors when invoking `rustc` or `cargo`.

Since we install Rust in a very similar way to upstream, it makes
sense to set the `RUNPATH` to `$ORIGIN/../lib` as their packaging
does and not pollute ld.so.conf with Rust paths.

This enables dev-lang/rust binaries to search relative to
their install location, and will therefore always respect EPREFIX.

Also drop obsolete 1.82.0-r100; no need to revbump that.

Closes: https://bugs.gentoo.org/949374
Signed-off-by: Matt Jolly <kangie@gentoo.org>
Signed-off-by: Sam James <sam@gentoo.org>

1 files changed, 1022 insertions, 0 deletions

diff --git a/dev-lang/rust/rust-1.74.1-r101.ebuild b/dev-lang/rust/rust-1.74.1-r101.ebuild
new file mode 100644
index 000000000000..e485a61f5057
--- /dev/null
+++ b/dev-lang/rust/rust-1.74.1-r101.ebuild
@@ -0,0 +1,1022 @@
+# Copyright 1999-2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+LLVM_COMPAT=( 17 )
+PYTHON_COMPAT=( python3_{10..12} )
+
+RUST_MAX_VER=${PV}
+RUST_MIN_VER="$(ver_cut 1).$(($(ver_cut 2) - 1)).0"
+RUST_OPTIONAL=1
+
+MRUSTC_VERSION="0.11.2"
+MRUSTC_RUST_VERSION="1.74.0"
+
+inherit check-reqs cmake edo estack flag-o-matic llvm-r1 multiprocessing multilib multilib-build \
+	optfeature python-any-r1 rust rust-toolchain toolchain-funcs verify-sig
+
+if [[ ${PV} = *beta* ]]; then
+	betaver=${PV//*beta}
+	BETA_SNAPSHOT="${betaver:0:4}-${betaver:4:2}-${betaver:6:2}"
+	MY_P="rustc-beta"
+	SRC="${BETA_SNAPSHOT}/rustc-beta-src.tar.xz -> rustc-${PV}-src.tar.xz"
+else
+	MY_P="rustc-${PV}"
+	SRC="${MY_P}-src.tar.xz"
+	KEYWORDS="amd64 arm arm64 ~loong ppc ppc64 ~riscv sparc x86"
+fi
+
+DESCRIPTION="Language empowering everyone to build reliable and efficient software"
+HOMEPAGE="https://www.rust-lang.org/"
+
+SRC_URI="
+	https://static.rust-lang.org/dist/${SRC}
+	verify-sig? ( https://static.rust-lang.org/dist/${SRC}.asc )
+"
+
+S="${WORKDIR}/${MY_P}-src"
+
+# keep in sync with llvm ebuild of the same version as bundled one.
+ALL_LLVM_TARGETS=( AArch64 AMDGPU ARC ARM AVR BPF CSKY DirectX Hexagon Lanai
+	LoongArch M68k Mips MSP430 NVPTX PowerPC RISCV Sparc SPIRV SystemZ VE
+	WebAssembly X86 XCore Xtensa )
+ALL_LLVM_TARGETS=( "${ALL_LLVM_TARGETS[@]/#/llvm_targets_}" )
+LLVM_TARGET_USEDEPS=${ALL_LLVM_TARGETS[@]/%/(-)?}
+
+ALL_LLVM_EXPERIMENTAL_TARGETS=( ARC CSKY DirectX M68k SPIRV Xtensa )
+
+LICENSE="|| ( MIT Apache-2.0 ) BSD BSD-1 BSD-2 BSD-4"
+SLOT="${PV}"
+
+IUSE="big-endian clippy cpu_flags_x86_sse2 debug dist doc llvm-libunwind +lto miri mrustc-bootstrap nightly parallel-compiler rustfmt rust-analyzer rust-src system-llvm test wasm ${ALL_LLVM_TARGETS[*]}"
+
+LLVM_DEPEND=()
+# splitting usedeps needed to avoid CI/pkgcheck's UncheckableDep limitation
+for _x in "${ALL_LLVM_TARGETS[@]}"; do
+	LLVM_DEPEND+=( "	${_x}? ( $(llvm_gen_dep "llvm-core/llvm:\${LLVM_SLOT}[${_x}]") )" )
+done
+LLVM_DEPEND+=( "	wasm? ( $(llvm_gen_dep 'llvm-core/lld:${LLVM_SLOT}') )" )
+LLVM_DEPEND+=( "	$(llvm_gen_dep 'llvm-core/llvm:${LLVM_SLOT}')" )
+
+BDEPEND="${PYTHON_DEPS}
+	app-eselect/eselect-rust
+	|| (
+		>=sys-devel/gcc-4.7
+		>=llvm-core/clang-3.5
+	)
+	!system-llvm? (
+		>=dev-build/cmake-3.13.4
+		app-alternatives/ninja
+	)
+	test? ( dev-debug/gdb )
+	verify-sig? ( sec-keys/openpgp-keys-rust )
+	mrustc-bootstrap? (
+		~dev-lang/mrustc-${MRUSTC_VERSION}
+		dev-build/cmake
+		sys-devel/gcc:*
+	)
+	!mrustc-bootstrap? ( ${RUST_DEPEND} )
+"
+
+DEPEND="
+	>=app-arch/xz-utils-5.2
+	net-misc/curl:=[http2,ssl]
+	sys-libs/zlib:=
+	dev-libs/openssl:0=
+	system-llvm? (
+		${LLVM_DEPEND[*]}
+		llvm-libunwind? ( llvm-runtimes/libunwind:= )
+	)
+	!system-llvm? (
+		!llvm-libunwind? (
+			elibc_musl? ( sys-libs/libunwind:= )
+		)
+	)
+"
+
+RDEPEND="${DEPEND}
+	app-eselect/eselect-rust
+	dev-lang/rust-common
+	sys-apps/lsb-release
+	!dev-lang/rust:stable
+	!dev-lang/rust-bin:stable
+"
+
+REQUIRED_USE="|| ( ${ALL_LLVM_TARGETS[*]} )
+	miri? ( nightly )
+	parallel-compiler? ( nightly )
+	rust-analyzer? ( rust-src )
+	test? ( ${ALL_LLVM_TARGETS[*]} )
+	wasm? ( llvm_targets_WebAssembly )
+	x86? ( cpu_flags_x86_sse2 )
+"
+
+# we don't use cmake.eclass, but can get a warning
+CMAKE_WARN_UNUSED_CLI=no
+
+QA_FLAGS_IGNORED="
+	usr/lib/${PN}/${PV}/bin/.*
+	usr/lib/${PN}/${PV}/libexec/.*
+	usr/lib/${PN}/${PV}/lib/lib.*.so
+	usr/lib/${PN}/${PV}/lib/rustlib/.*/bin/.*
+	usr/lib/${PN}/${PV}/lib/rustlib/.*/lib/lib.*.so
+"
+
+QA_SONAME="
+	usr/lib/${PN}/${PV}/lib/lib.*.so.*
+	usr/lib/${PN}/${PV}/lib/rustlib/.*/lib/lib.*.so
+"
+
+QA_PRESTRIPPED="
+	usr/lib/${PN}/${PV}/lib/rustlib/.*/bin/rust-llvm-dwp
+	usr/lib/${PN}/${PV}/lib/rustlib/.*/lib/self-contained/crtn.o
+"
+
+# An rmeta file is custom binary format that contains the metadata for the crate.
+# rmeta files do not support linking, since they do not contain compiled object files.
+# so we can safely silence the warning for this QA check.
+QA_EXECSTACK="usr/lib/${PN}/${PV}/lib/rustlib/*/lib*.rlib:lib.rmeta"
+
+# causes double bootstrap
+RESTRICT="test"
+
+VERIFY_SIG_OPENPGP_KEY_PATH=/usr/share/openpgp-keys/rust.asc
+
+PATCHES=(
+	"${FILESDIR}"/1.74.1-cross-compile-libz.patch
+	#"${FILESDIR}"/1.72.0-bump-libc-deps-to-0.2.146.patch  # pending refresh
+	"${FILESDIR}"/1.70.0-ignore-broken-and-non-applicable-tests.patch
+	"${FILESDIR}"/1.62.1-musl-dynamic-linking.patch
+	"${FILESDIR}"/1.67.0-doc-wasm.patch
+)
+
+clear_vendor_checksums() {
+	sed -i 's/\("files":{\)[^}]*/\1/' "vendor/${1}/.cargo-checksum.json" || die
+}
+
+toml_usex() {
+	usex "${1}" true false
+}
+
+pre_build_checks() {
+	local M=9216
+	# multiply requirements by 1.3 if we are doing x86-multilib
+	if use amd64; then
+		M=$(( $(usex abi_x86_32 13 10) * ${M} / 10 ))
+	fi
+	M=$(( $(usex clippy 128 0) + ${M} ))
+	M=$(( $(usex miri 128 0) + ${M} ))
+	M=$(( $(usex rustfmt 256 0) + ${M} ))
+	# add 2G if we compile llvm and 256M per llvm_target
+	if ! use system-llvm; then
+		M=$(( 2048 + ${M} ))
+		local ltarget
+		for ltarget in ${ALL_LLVM_TARGETS[@]}; do
+			M=$(( $(usex ${ltarget} 256 0) + ${M} ))
+		done
+	fi
+	M=$(( $(usex wasm 256 0) + ${M} ))
+	M=$(( $(usex debug 2 1) * ${M} ))
+	eshopts_push -s extglob
+	if is-flagq '-g?(gdb)?([1-9])'; then
+		M=$(( 15 * ${M} / 10 ))
+	fi
+	eshopts_pop
+	M=$(( $(usex doc 256 0) + ${M} ))
+	if use mrustc-bootstrap; then
+		M=$(( 2 * ${M} ))
+	fi
+	CHECKREQS_DISK_BUILD=${M}M check-reqs_pkg_${EBUILD_PHASE}
+}
+
+llvm_check_deps() {
+	has_version -r "llvm-core/llvm:${LLVM_SLOT}[${LLVM_TARGET_USEDEPS// /,}]"
+}
+
+# Is LLVM being linked against libc++?
+is_libcxx_linked() {
+	local code='#include <ciso646>
+#if defined(_LIBCPP_VERSION)
+	HAVE_LIBCXX
+#endif
+'
+	local out=$($(tc-getCXX) ${CXXFLAGS} ${CPPFLAGS} -x c++ -E -P - <<<"${code}") || return 1
+	[[ ${out} == *HAVE_LIBCXX* ]]
+}
+
+pkg_pretend() {
+	pre_build_checks
+}
+
+pkg_setup() {
+	if [[ ${MERGE_TYPE} != binary ]]; then
+		pre_build_checks
+		python-any-r1_pkg_setup
+
+		export LIBGIT2_NO_PKG_CONFIG=1 #749381
+		if tc-is-cross-compiler; then
+			use system-llvm && die "USE=system-llvm not allowed when cross-compiling"
+			local cross_llvm_target="$(llvm_tuple_to_target "${CBUILD}")"
+			use "llvm_targets_${cross_llvm_target}" || \
+				die "Must enable LLVM_TARGETS=${cross_llvm_target} matching CBUILD=${CBUILD} when cross-compiling"
+		fi
+
+		if use mrustc-bootstrap; then
+			if ! tc-is-gcc; then
+				die "USE=mrustc-bootstrap reqires that the build environment use GCC"
+			fi
+		else
+			rust_pkg_setup
+		fi
+
+		if use system-llvm; then
+			llvm-r1_pkg_setup
+
+			local llvm_config="$(get_llvm_prefix)/bin/llvm-config"
+			export LLVM_LINK_SHARED=1
+			export RUSTFLAGS="${RUSTFLAGS} -Lnative=$("${llvm_config}" --libdir)"
+		fi
+	fi
+}
+
+src_prepare() {
+	default
+	# We'll need to revert this after the bootstrap.
+	if use mrustc-bootstrap; then
+		pushd "${S}" 2>/dev/null || die
+		patch -p0 < "${BROOT}"/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-src.patch ||
+			die "Failed to patch sources to enable bootstrap with mrustc"
+		popd 2>/dev/null || die
+	fi
+}
+
+src_configure() {
+	if tc-is-cross-compiler; then
+		export PKG_CONFIG_ALLOW_CROSS=1
+		export PKG_CONFIG_PATH="${ESYSROOT}/usr/$(get_libdir)/pkgconfig"
+		export OPENSSL_INCLUDE_DIR="${ESYSROOT}/usr/include"
+		export OPENSSL_LIB_DIR="${ESYSROOT}/usr/$(get_libdir)"
+	fi
+
+	filter-lto # https://bugs.gentoo.org/862109 https://bugs.gentoo.org/866231
+
+	local rust_target="" rust_targets="" arch_cflags
+
+	# Collect rust target names to compile standard libs for all ABIs.
+	for v in $(multilib_get_enabled_abi_pairs); do
+		rust_targets+=",\"$(rust_abi $(get_abi_CHOST ${v##*.}))\""
+	done
+	if use wasm; then
+		rust_targets+=",\"wasm32-unknown-unknown\""
+		if use system-llvm; then
+			# un-hardcode rust-lld linker for this target
+			# https://bugs.gentoo.org/715348
+			sed -i '/linker:/ s/rust-lld/wasm-ld/' compiler/rustc_target/src/spec/wasm_base.rs || die
+		fi
+	fi
+	rust_targets="${rust_targets#,}"
+
+	# cargo and rustdoc are mandatory and should always be included
+	local tools='"cargo","rustdoc", "rust-demangler"'
+	use clippy && tools+=',"clippy"'
+	use miri && tools+=',"miri"'
+	use rustfmt && tools+=',"rustfmt"'
+	use rust-analyzer && tools+=',"rust-analyzer"'
+	use rust-src && tools+=',"src"'
+
+	if use mrustc-bootstrap; then
+		local rust_stage0_root="${WORKDIR}/bootstrap/rust-${PV}"
+	else
+		local rust_stage0_root="$(${RUSTC} --print sysroot || die "Can't determine rust's sysroot")"
+		# in case of prefix it will be already prefixed, as --print sysroot returns full path
+		[[ -d ${rust_stage0_root} ]] || die "${rust_stage0_root} is not a directory"
+	fi
+
+	rust_target="$(rust_abi)"
+	rust_build="$(rust_abi "${CBUILD}")"
+	rust_host="$(rust_abi "${CHOST}")"
+
+	LLVM_EXPERIMENTAL_TARGETS=()
+	for _x in "${ALL_LLVM_EXPERIMENTAL_TARGETS[@]}"; do
+		if use llvm_targets_${_x} ; then
+			LLVM_EXPERIMENTAL_TARGETS+=( ${_x} )
+		fi
+	done
+	LLVM_EXPERIMENTAL_TARGETS=${LLVM_EXPERIMENTAL_TARGETS[@]}
+
+	local cm_btype="$(usex debug DEBUG RELEASE)"
+	cat <<- _EOF_ > "${S}"/config.toml
+		changelog-seen = 2
+		[llvm]
+		download-ci-llvm = false
+		optimize = $(toml_usex !debug)
+		release-debuginfo = $(toml_usex debug)
+		assertions = $(toml_usex debug)
+		ninja = true
+		targets = "${LLVM_TARGETS// /;}"
+		experimental-targets = "${LLVM_EXPERIMENTAL_TARGETS// /;}"
+		link-shared = $(toml_usex system-llvm)
+		$(if is_libcxx_linked; then
+			# https://bugs.gentoo.org/732632
+			echo "use-libcxx = true"
+			echo "static-libstdcpp = false"
+		fi)
+		$(case "${rust_target}" in
+			i586-*-linux-*)
+				# https://github.com/rust-lang/rust/issues/93059
+				echo 'cflags = "-fcf-protection=none"'
+				echo 'cxxflags = "-fcf-protection=none"'
+				echo 'ldflags = "-fcf-protection=none"'
+				;;
+			*)
+				;;
+		esac)
+		enable-warnings = false
+		[llvm.build-config]
+		CMAKE_VERBOSE_MAKEFILE = "ON"
+		$(if ! tc-is-cross-compiler; then
+			# When cross-compiling, LLVM is compiled twice, once for host and
+			# once for target.  Unfortunately, this build configuration applies
+			# to both, which means any flags applicable to one target but not
+			# the other will break.  Conditionally disable respecting user
+			# flags when cross-compiling.
+			echo "CMAKE_C_FLAGS_${cm_btype} = \"${CFLAGS}\""
+			echo "CMAKE_CXX_FLAGS_${cm_btype} = \"${CXXFLAGS}\""
+			echo "CMAKE_EXE_LINKER_FLAGS_${cm_btype} = \"${LDFLAGS}\""
+			echo "CMAKE_MODULE_LINKER_FLAGS_${cm_btype} = \"${LDFLAGS}\""
+			echo "CMAKE_SHARED_LINKER_FLAGS_${cm_btype} = \"${LDFLAGS}\""
+			echo "CMAKE_STATIC_LINKER_FLAGS_${cm_btype} = \"${ARFLAGS}\""
+		fi)
+		[build]
+		build-stage = 2
+		test-stage = 2
+		build = "${rust_build}"
+		host = ["${rust_host}"]
+		target = [${rust_targets}]
+		cargo = "${rust_stage0_root}/bin/cargo"
+		rustc = "${rust_stage0_root}/bin/rustc"
+		rustfmt = "${rust_stage0_root}/bin/rustfmt"
+		docs = $(toml_usex doc)
+		compiler-docs = false
+		submodules = false
+		python = "${EPYTHON}"
+		locked-deps = true
+		vendor = true
+		extended = true
+		tools = [${tools}]
+		verbose = 2
+		sanitizers = false
+		profiler = true
+		cargo-native-static = false
+		[install]
+		prefix = "${EPREFIX}/usr/lib/${PN}/${PV}"
+		sysconfdir = "etc"
+		docdir = "share/doc/rust"
+		bindir = "bin"
+		libdir = "lib"
+		mandir = "share/man"
+		[rust]
+		# https://github.com/rust-lang/rust/issues/54872
+		codegen-units-std = 1
+		optimize = true
+		debug = $(toml_usex debug)
+		debug-assertions = $(toml_usex debug)
+		debug-assertions-std = $(toml_usex debug)
+		debuginfo-level = $(usex debug 2 0)
+		debuginfo-level-rustc = $(usex debug 2 0)
+		debuginfo-level-std = $(usex debug 2 0)
+		debuginfo-level-tools = $(usex debug 2 0)
+		debuginfo-level-tests = 0
+		backtrace = true
+		incremental = false
+		$(if ! tc-is-cross-compiler; then
+			echo "default-linker = \"$(tc-getCC)\""
+		fi)
+		parallel-compiler = $(toml_usex parallel-compiler)
+		channel = "$(usex nightly nightly stable)"
+		description = "gentoo"
+		rpath = true
+		verbose-tests = true
+		optimize-tests = $(toml_usex !debug)
+		codegen-tests = true
+		dist-src = false
+		remap-debuginfo = true
+		lld = $(usex system-llvm false $(toml_usex wasm))
+		# only deny warnings if doc+wasm are NOT requested, documenting stage0 wasm std fails without it
+		# https://github.com/rust-lang/rust/issues/74976
+		# https://github.com/rust-lang/rust/issues/76526
+		deny-warnings = $(usex wasm $(usex doc false true) true)
+		backtrace-on-ice = true
+		jemalloc = false
+		lto = "$(usex lto fat off)"
+		[dist]
+		src-tarball = false
+		compression-formats = ["xz"]
+		compression-profile = "balanced"
+	_EOF_
+
+	for v in $(multilib_get_enabled_abi_pairs); do
+		rust_target=$(rust_abi $(get_abi_CHOST ${v##*.}))
+		arch_cflags="$(get_abi_CFLAGS ${v##*.})"
+
+		export CFLAGS_${rust_target//-/_}="${arch_cflags}"
+
+		cat <<- _EOF_ >> "${S}"/config.toml
+			[target.${rust_target}]
+			ar = "$(tc-getAR)"
+			cc = "$(tc-getCC)"
+			cxx = "$(tc-getCXX)"
+			linker = "$(tc-getCC)"
+			ranlib = "$(tc-getRANLIB)"
+			llvm-libunwind = "$(usex llvm-libunwind $(usex system-llvm system in-tree) no)"
+		_EOF_
+		if use system-llvm; then
+			cat <<- _EOF_ >> "${S}"/config.toml
+				llvm-config = "$(get_llvm_prefix)/bin/llvm-config"
+			_EOF_
+		fi
+		# by default librustc_target/spec/linux_musl_base.rs sets base.crt_static_default = true;
+		# but we patch it and set to false here as well
+		if use elibc_musl; then
+			cat <<- _EOF_ >> "${S}"/config.toml
+				crt-static = false
+			_EOF_
+		fi
+	done
+	if use wasm; then
+		cat <<- _EOF_ >> "${S}"/config.toml
+			[target.wasm32-unknown-unknown]
+			linker = "$(usex system-llvm lld rust-lld)"
+			# wasm target does not have profiler_builtins https://bugs.gentoo.org/848483
+			profiler = false
+		_EOF_
+	fi
+
+	if [[ -n ${I_KNOW_WHAT_I_AM_DOING_CROSS} ]]; then # whitespace intentionally shifted below
+	# experimental cross support
+	# discussion: https://bugs.gentoo.org/679878
+	# TODO: c*flags, clang, system-llvm, cargo.eclass target support
+	# it would be much better if we could split out stdlib
+	# complilation to separate ebuild and abuse CATEGORY to
+	# just install to /usr/lib/rustlib/<target>
+
+	# extra targets defined as a bash array
+	# spec format:  <LLVM target>:<rust-target>:<CTARGET>
+	# best place would be /etc/portage/env/dev-lang/rust
+	# Example:
+	# RUST_CROSS_TARGETS=(
+	#	"AArch64:aarch64-unknown-linux-gnu:aarch64-unknown-linux-gnu"
+	# )
+	# no extra hand holding is done, no target transformations, all
+	# values are passed as-is with just basic checks, so it's up to user to supply correct values
+	# valid rust targets can be obtained with
+	# 	rustc --print target-list
+	# matching cross toolchain has to be installed
+	# matching LLVM_TARGET has to be enabled for both rust and llvm (if using system one)
+	# only gcc toolchains installed with crossdev are checked for now.
+
+	# BUG: we can't pass host flags to cross compiler, so just filter for now
+	# BUG: this should be more fine-grained.
+	filter-flags '-mcpu=*' '-march=*' '-mtune=*'
+
+	local cross_target_spec
+	for cross_target_spec in "${RUST_CROSS_TARGETS[@]}";do
+		# extracts first element form <LLVM target>:<rust-target>:<CTARGET>
+		local cross_llvm_target="${cross_target_spec%%:*}"
+		# extracts toolchain triples, <rust-target>:<CTARGET>
+		local cross_triples="${cross_target_spec#*:}"
+		# extracts first element after before : separator
+		local cross_rust_target="${cross_triples%%:*}"
+		# extracts last element after : separator
+		local cross_toolchain="${cross_triples##*:}"
+		use llvm_targets_${cross_llvm_target} || die "need llvm_targets_${cross_llvm_target} target enabled"
+		command -v ${cross_toolchain}-gcc > /dev/null 2>&1 || die "need ${cross_toolchain} cross toolchain"
+
+		cat <<- _EOF_ >> "${S}"/config.toml
+			[target.${cross_rust_target}]
+			ar = "${cross_toolchain}-ar"
+			cc = "${cross_toolchain}-gcc"
+			cxx = "${cross_toolchain}-g++"
+			linker = "${cross_toolchain}-gcc"
+			ranlib = "${cross_toolchain}-ranlib"
+		_EOF_
+		if use system-llvm; then
+			cat <<- _EOF_ >> "${S}"/config.toml
+				llvm-config = "$(get_llvm_prefix)/bin/llvm-config"
+			_EOF_
+		fi
+		if [[ "${cross_toolchain}" == *-musl* ]]; then
+			cat <<- _EOF_ >> "${S}"/config.toml
+				musl-root = "$(${cross_toolchain}-gcc -print-sysroot)/usr"
+			_EOF_
+		fi
+
+		# append cross target to "normal" target list
+		# example 'target = ["powerpc64le-unknown-linux-gnu"]'
+		# becomes 'target = ["powerpc64le-unknown-linux-gnu","aarch64-unknown-linux-gnu"]'
+
+		rust_targets="${rust_targets},\"${cross_rust_target}\""
+		sed -i "/^target = \[/ s#\[.*\]#\[${rust_targets}\]#" config.toml || die
+
+		ewarn
+		ewarn "Enabled ${cross_rust_target} rust target"
+		ewarn "Using ${cross_toolchain} cross toolchain"
+		ewarn
+		if ! has_version -b 'sys-devel/binutils[multitarget]' ; then
+			ewarn "'sys-devel/binutils[multitarget]' is not installed"
+			ewarn "'strip' will be unable to strip cross libraries"
+			ewarn "cross targets will be installed with full debug information"
+			ewarn "enable 'multitarget' USE flag for binutils to be able to strip object files"
+			ewarn
+			ewarn "Alternatively llvm-strip can be used, it supports stripping any target"
+			ewarn "define STRIP=\"llvm-strip\" to use it (experimental)"
+			ewarn
+		fi
+	done
+	fi # I_KNOW_WHAT_I_AM_DOING_CROSS
+
+	einfo "Rust configured with the following flags:"
+	echo
+	echo RUSTFLAGS="\"${RUSTFLAGS}\""
+	echo RUSTFLAGS_BOOTSTRAP="\"${RUSTFLAGS_BOOTSTRAP}\""
+	echo RUSTFLAGS_NOT_BOOTSTRAP="\"${RUSTFLAGS_NOT_BOOTSTRAP}\""
+	echo MAGIC_EXTRA_RUSTFLAGS="\"${MAGIC_EXTRA_RUSTFLAGS}\""
+	env | grep "CARGO_TARGET_.*_RUSTFLAGS="
+	env | grep "CFLAGS_.*"
+	echo
+	einfo "config.toml contents:"
+	cat "${S}"/config.toml || die
+	echo
+}
+
+# Build a very minimal llvm that we can use for bootstrap rustc codegen
+llvm_bootstrap() {
+	# Reference ${P}/src/bootstrap/native.rs for these values
+	local llvm_cmake_opts=(
+		"-G Ninja"
+		"-DLLVM_TARGET_ARCH=${CFG_COMPILER_HOST_TRIPLE%%-*}"
+		"-DLLVM_DEFAULT_TARGET_TRIPLE=${CFG_COMPILER_HOST_TRIPLE}"
+		"-DLLVM_TARGETS_TO_BUILD=${BOOTSTRAP_LLVM_TARGETS:=X86;ARM;AArch64}" #;Mips;PowerPC;SystemZ;JSBackend;MSP430;Sparc;NVPTX
+		"-DLLVM_ENABLE_ASSERTIONS=OFF"
+		"-DLLVM_INCLUDE_EXAMPLES=OFF"
+		"-DLLVM_INCLUDE_TESTS=OFF"
+		"-DLLVM_INCLUDE_DOCS=OFF"
+		"-DLLVM_INCLUDE_BENCHMARKS=OFF"
+		"-DLLVM_ENABLE_ZLIB=OFF"
+		"-DLLVM_ENABLE_TERMINFO=OFF"
+		"-DLLVM_ENABLE_LIBEDIT=OFF"
+		"-DCMAKE_CXX_COMPILER=$(tc-getCXX)"
+		"-DCMAKE_C_COMPILER=$(tc-getCC)"
+		"-DCMAKE_BUILD_TYPE=Release"
+	)
+
+	if [[ -z "${LLVM_CMAKE_OPTS_EXTRA}" ]]; then
+		llvm_cmake_opts+=( "${LLVM_CMAKE_OPTS_EXTRA}")
+	fi
+
+	elog "Building bootstrap llvm ..."
+
+	mkdir -p "${WORKDIR}/bootstrap/llvm" || die
+	pushd "${WORKDIR}/bootstrap/llvm" 2>/dev/null || die
+		edo cmake ${llvm_cmake_opts[*]} "${S}/src/llvm-project/llvm"
+		eninja || die "Failed to build bootstrap llvm"
+	popd 2>/dev/null || die
+}
+
+# High level steps:
+# Our system mrustc package has built stdlib for our current platform.
+# - Step 1: Use system-installed mrustc, (m)rust(c) stdlib, and minicargo to
+#	bootstrap a `cargo` and `rustc` (mrustc-stage0)
+# - Step 2: Use minicargo and the built `rustc` to build a working `sysroot`
+#			(includes `std`, `panic_unwind``, `test`, etc.) (mrustc-stage0)
+# - Step 3: Build build libs again (this time using `cargo` and `rustc`) (mrustc-stage1)
+# - Step 4: Build a `rustc` using those libs (mrustc-stage1)
+#  - Done so there's an optimised rustc arollvm_cmake_optsund (mrustc is bad at codegen)
+# - Step 5: Build `libstd` with this `rustc` (mrustc-stage2)
+#  - Needed to match ABIs
+# Stages:
+# - mrustc-stage0: mrustc-built cargo and rustc
+# - mrustc-stage1: rustc and sysroot built with mrustc-stage0
+# - mrustc-stage2: rustc from stage1 with sysroot built with stage0
+# See:
+# - https://github.com/thepowersgang/mrustc/blob/master/run_rustc/Makefile
+# - https://github.com/thepowersgang/mrustc/blob/master/TestRustcBootstrap.sh
+# - Upstream Windows .cmd files are also a good reference for early bootstrap
+mrustc_bootstrap() {
+	export RUSTC_BOOTSTRAP=1 # Possibly the only intended use of this variable in ::gentoo
+	# export these variables now and unset them at the end of the function so they don't leak
+	# into the rest of the build.
+	export CFG_COMPILER_HOST_TRIPLE="$(rust_abi)"
+	export CFG_RELEASE="${MRUSTC_RUST_VERSION}"	# Let's pretend we're 1.74.0
+	export CFG_RELEASE_CHANNEL="stable"
+	export CFG_VERSION="${MRUSTC_RUST_VERSION}-stable-mrustc"
+	export CFG_PREFIX="mrustc"
+	export CFG_LIBDIR_RELATIVE="lib"
+	export RUSTC_INSTALL_BINDIR="bin"
+	export REAL_LIBRARY_PATH_VAR="LD_LIBRARY_PATH"
+
+	# These flags are used in every invocation of our bootstrap `cargo`.
+	local cargo_flags="--target ${CFG_COMPILER_HOST_TRIPLE} -j $(makeopts_jobs) --release --verbose"
+
+	if use system-llvm; then
+		export LLVM_CONFIG="$(get_llvm_prefix)/bin/llvm-config"
+	else
+		llvm_bootstrap
+		export LLVM_CONFIG="${WORKDIR}/bootstrap/llvm/bin/llvm-config"
+	fi
+
+	# define the mrustc sysroot and common minicargo arguments.
+	local mrustc_sysroot="${BROOT}/usr/lib/rust/mrustc-${MRUSTC_VERSION}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"
+	local minicargo_common_args=(
+		"-L" "${mrustc_sysroot}"
+		"-j" "$(makeopts_jobs)"
+		"--vendor-dir" "${S}/vendor"
+		"--manifest-overrides"
+		"${BROOT}/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-overrides.toml"
+	)
+	# There's a very good chance that minicargo and mrustc are not in the PATH.
+	if ! command -v minicargo &> /dev/null; then
+		export PATH="${BROOT}/usr/lib/rust/mrustc-${MRUSTC_VERSION}/bin:${PATH}"
+	fi
+	# Sanity check our bootstrap compiler & stdlib.
+	elog "Sanity checking mrustc and stdlib ..."
+	edo mrustc "${S}/tests/ui/hello_world/main.rs" -L "${mrustc_sysroot}" -o "${T}"/hello -g
+	"${T}"/hello || die "Failed to run hello_world"
+	# Seems fine, let's build some tools!
+
+	# Step 1: Build a `cargo` and `rustc` using system-installed mrustc
+	# Anything we produce is going to be terribly unoptimised; mrustc does not do fantastic codegen.
+	# It's good enough to bootstrap the "real" rustc though.
+	elog "Building bootstrap cargo and rustc using mrustc and minicargo (mrustc-stage0) ..."
+	local stage0="${WORKDIR}/bootstrap/mrustc-stage0"
+	mkdir -p "${stage0}" || die
+	edo minicargo "${S}"/src/tools/cargo --output-dir "${stage0}"/cargo-build ${minicargo_common_args[*]}
+	"${stage0}"/cargo-build/cargo --version || die "Bootstrap cargo failed basic sanity check"
+	edo minicargo "${S}"/compiler/rustc --output-dir "${stage0}"/rustc-build ${minicargo_common_args[*]} \
+		--features llvm
+	"${stage0}"/rustc-build/rustc_main --version || die "Bootstrap rustc failed basic sanity check"
+	# minicargo has special-casing for `rustc` so we need to rename it.
+	mv "${stage0}"/rustc-build/rustc_main "${stage0}"/rustc-build/rustc || die "Failed to rename rustc_main to rustc"
+	# rustc wants these here
+	mkdir -p "${stage0}"/codegen-backends || die
+	mv "${stage0}"/rustc-build/librustc_codegen_llvm.* "${stage0}"/codegen-backends || die
+
+	# Step 2: use the bootstrapped rustc to build sysroot; we need to use `minicargo` for this -
+	# mrustc does not accept all of the arguments that rustc does, even with the rustc_proxy wrapper.
+	# `--script-overrides`:  If the overrides are available, build scripts (and build-deps) are not built
+	# which is good since we don't have a working compiler yet, and can't build them.
+
+	local stage0_sysroot_lib="${stage0}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"
+	# minicargo <= 0.11.2 doesn't create this directory and silently fails, besides it's better to be explicit, right?
+	mkdir -p "${stage0_sysroot_lib}" || die "Failed to create stage0 directory"
+
+	elog "Building 'sysroot' using bootstrap rustc (mrustc-stage0) ..."
+	edo env MRUSTC_PATH="${stage0}/rustc-build/rustc" minicargo -j $(makeopts_jobs) --vendor-dir "${S}"/vendor \
+		--script-overrides  "${BROOT}/usr/share/mrustc-0.11.2/script-overrides/stable-${MRUSTC_RUST_VERSION}-linux/" \
+		--output-dir "${stage0_sysroot_lib}" "${S}"/library/sysroot ||
+			die "Failed to build sysroot with bootstrap rust (mrustc-stage0)"
+
+	elog "Sanity checking sysroot and rustc ..."
+	mkdir -p "${T}"/stage0-hello || die
+	edo "${stage0}"/rustc-build/rustc -L "${stage0_sysroot_lib}" -g "${S}/tests/ui/hello_world/main.rs" \
+		-o "${T}"/stage0-hello/hello
+	"${T}"/stage0-hello/hello || die "Failed to run hello_world built with bootstrap rust stage0"
+
+	elog "mrustc bootstrap stage0 complete!"
+
+	# Step 3: Build a "proper" libstd, including dynamic libs using our bootstrap cargo and rustc.
+	elog "Building 'sysroot' with the stage0 rustc (mrustc-stage1) ..."
+	local stage1="${WORKDIR}/bootstrap/mrustc-stage1"
+	local stage1_sysroot_lib="${stage1}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"
+	mkdir -p "${stage1_sysroot_lib}" || die "Failed to create stage1 directory"
+	mkdir -p "${stage1}/bin" || die
+
+	# Simplified to avoid calling rustc_proxy; We don't need stage1 rustc until after this is built...
+	edo env RUSTFLAGS="-Z force-unstable-if-unmarked" CARGO_TARGET_DIR="${stage1}/sysroot-build" \
+		RUSTC="${stage0}/rustc-build/rustc" "${stage0}"/cargo-build/cargo build ${cargo_flags} \
+		--manifest-path "${S}/library/sysroot/Cargo.toml" --features panic-unwind
+
+	# Move the built libs into the sysroot libdir.
+	mv "${stage1}/sysroot-build/${CFG_COMPILER_HOST_TRIPLE}/release/deps"/*.{rlib,rmeta,so} \
+		"${stage1_sysroot_lib}" || die "Failed to move stage1 libs to stage1 sysroot"
+
+	# We need to copy the stage0 rustc to the stage1 sysroot; this "updates" the sysroot location and enables
+	# resolution of stage1 libs. (run `rustc --print sysroot` on stage0 and stage1 rustc to verify)
+	cp "${stage0}/rustc-build/rustc" "${stage1}/bin/rustc" || die "Failed to copy rustc to stage1 sysroot"
+
+	# Step 4: Build `rustc` with itself, so we have a rustc with the right ABI.
+	# This will be our final `rustc` for the bootstrap process.
+	elog "Building rustc with stage1 libs (mrustc-stage1) ..."
+	mkdir -p "${stage1}/rustc-build" || die
+	edo env RUSTFLAGS="-Z force-unstable-if-unmarked -C link_args=-Wl,-rpath,\$ORIGIN/../lib" \
+		LD_LIBRARY_PATH="${stage2_sysroot_lib}" CARGO_TARGET_DIR="${stage1}/rustc-build" \
+		RUSTC="${stage1}/bin/rustc" TMPDIR="${T}" "${stage0}"/cargo-build/cargo build ${cargo_flags} \
+		--manifest-path "${S}/compiler/rustc/Cargo.toml"  --features llvm
+
+	# Step 5: Build `sysroot` with this `rustc` - Needed to match ABI
+	# We need to use the previous sysroot; we could reuse that dir but it's easier to just copy it.
+	elog "Building final 'sysroot' with the final rustc (mrustc-stage2) ..."
+	local stage2="${WORKDIR}/bootstrap/mrustc-stage2"
+	local stage2_sysroot_lib="${stage2}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"
+	mkdir -p "${stage2_sysroot_lib}" || die "Failed to create stage2 directory"
+	mkdir -p "${stage2}/bin" || die
+
+	# Copy required files from stage1 to stage2 sysroot
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/rustc-main "${stage2}/bin/rustc_binary" ||
+		die "Failed to copy final rustc to stage2 sysroot"
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/librustc_driver.so "${stage2}/lib" ||
+		die "Failed to copy librustc_driver to sysroot"
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/deps/*.{rlib,so} "${stage2_sysroot_lib}" ||
+		die "Failed to copy final rustc libs to stage2 sysroot"
+	cp "${stage1_sysroot_lib}"/* "${stage2_sysroot_lib}" || die "Failed to copy stage1 so files to stage2 sysroot"
+
+	# There's a magic script used in place of rustc so that libs can be found
+	cat <<- EOF > "${stage2}/bin/rustc" || die "Failed to create rustc wrapper"
+		#!/bin/sh
+		LD_LIBRARY_PATH="${stage2}/lib:${stage2_sysroot_lib}" ${stage2}/bin/rustc_binary "\$@"
+	EOF
+	chmod +x "${stage2}/bin/rustc" || die "Failed to make rustc wrapper executable"
+
+	# Use rustc to build 'sysroot'; this is the final step in the bootstrap process.
+	# rpath probably isn't needed here, but it doesn't hurt.
+	edo env RUSTFLAGS="-Z force-unstable-if-unmarked -C link_args=-Wl,-rpath,\$ORIGIN/../lib" \
+		CARGO_TARGET_DIR="${stage2}/stdlib-build" RUSTC="${stage2}/bin/rustc" \
+		"${stage0}"/cargo-build/cargo build ${cargo_flags} --manifest-path "${S}/library/sysroot/Cargo.toml" \
+		--features panic-unwind
+
+	# Build our final output sysroot
+	local output="${WORKDIR}/bootstrap/rust-${PV}"
+	local output_sysroot_lib="${output}/lib/rustlib/${CFG_COMPILER_HOST_TRIPLE}/lib"
+	mkdir -p "${output_sysroot_lib}" || die "Failed to create output directory"
+	mkdir -p "${output}/bin" || die "Failed to create output directory"
+
+	# Copy our various output files into the output sysroot
+	# rustc
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/rustc-main "${output}/bin/rustc_binary" ||
+		die "Failed to copy final rustc to output"
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/librustc_driver.so "${output}/lib" ||
+		die "Failed to copy librustc_driver to output"
+	cp "${stage1}/rustc-build/${CFG_COMPILER_HOST_TRIPLE}"/release/deps/*.{rlib,so} "${output_sysroot_lib}" ||
+		die "Failed to copy final rustc libs to output"
+	# cargo; no need to build an optimised cargo if we're using this to build a complelety new Rust.
+	cp "${stage0}/cargo-build/cargo" "${output}/bin/cargo" || die "Failed to copy cargo to output"
+	# libs
+	mv "${stage2}/stdlib-build/${CFG_COMPILER_HOST_TRIPLE}/release/deps"/*.{rlib,rmeta,so} "${output_sysroot_lib}" ||
+		die "Failed to copy stage2 libs to output"
+	# Our trusty rustc wrapper
+	cat <<- EOF > "${output}/bin/rustc" || die "Failed to create rustc wrapper"
+		#!/bin/sh
+		LD_LIBRARY_PATH="${output}/lib:${output_sysroot_lib}" ${output}/bin/rustc_binary "\$@"
+	EOF
+	chmod +x "${output}/bin/rustc" || die "Failed to make rustc wrapper executable"
+
+	# Perform a sanity check on the final Rust.
+	mkdir -p "${T}"/output-hello || die
+	edo "${output}/bin/rustc" -L "${output_sysroot_lib}" -g "${S}/tests/ui/hello_world/main.rs" \
+		-o "${T}"/output-hello/hello
+	"${T}"/output-hello/hello || die "Failed to run hello_world built with bootstrapped Rust"
+
+	elog "Successfully bootstrapped Rust using mrustc!"
+
+	# Note: The Rust sysroot that we've produced is pretty close to what we'd expect from a normal Rust build.
+	# If someone was so inclined they could build an optimised cargo using the stage2 rustc and sysroot,
+	# and install the output directly. This is untested, as I'm sure there's more to it than that.
+	# I'm satisfied with being able to build Rust normally at this point.
+
+	# Tidy up the Rust sources; revert mrustc changes so Rust can be built normally.
+	pushd "${S}" 2>/dev/null || die
+		patch -R -p0 < "${BROOT}"/usr/share/mrustc-${MRUSTC_VERSION}/patches/rustc-${MRUSTC_RUST_VERSION}-src.patch ||
+			die "Failed to revert mrustc patches"
+	popd 2>/dev/null || die
+
+	# Tidy up any environment variables we've set in the bootstrap process.
+	unset CFG_COMPILER_HOST_TRIPLE CFG_RELEASE CFG_RELEASE_CHANNEL CFG_PREFIX CFG_VERSION
+	unset CFG_LIBDIR_RELATIVE LLVM_CONFIG REAL_LIBRARY_PATH_VAR RUSTFLAGS RUSTC_BOOTSTRAP RUSTC_INSTALL_BINDIR
+}
+
+src_compile() {
+	use mrustc-bootstrap && mrustc_bootstrap
+	RUST_BACKTRACE=1 "${EPYTHON}" ./x.py build -vvv --config="${S}"/config.toml -j$(makeopts_jobs) || die
+}
+
+src_test() {
+	# https://rustc-dev-guide.rust-lang.org/tests/intro.html
+
+	# those are basic and codegen tests.
+	local tests=(
+		codegen
+		codegen-units
+		compile-fail
+		incremental
+		mir-opt
+		pretty
+		run-make
+	)
+
+	# fails if llvm is not built with ALL targets.
+	# and known to fail with system llvm sometimes.
+	use system-llvm || tests+=( assembly )
+
+	# fragile/expensive/less important tests
+	# or tests that require extra builds
+	# TODO: instead of skipping, just make some nonfatal.
+	if [[ ${ERUST_RUN_EXTRA_TESTS:-no} != no ]]; then
+		tests+=(
+			rustdoc
+			rustdoc-js
+			rustdoc-js-std
+			rustdoc-ui
+			run-make-fulldeps
+			ui
+			ui-fulldeps
+		)
+	fi
+
+	local i failed=()
+	einfo "rust_src_test: enabled tests ${tests[@]/#/src/test/}"
+	for i in "${tests[@]}"; do
+		local t="src/test/${i}"
+		einfo "rust_src_test: running ${t}"
+		if ! RUST_BACKTRACE=1 "${EPYTHON}" ./x.py test -vv --config="${S}"/config.toml \
+				-j$(makeopts_jobs) --no-doc --no-fail-fast "${t}"
+		then
+				failed+=( "${t}" )
+				eerror "rust_src_test: ${t} failed"
+		fi
+	done
+
+	if [[ ${#failed[@]} -ne 0 ]]; then
+		eerror "rust_src_test: failure summary: ${failed[@]}"
+		die "aborting due to test failures"
+	fi
+}
+
+src_install() {
+	DESTDIR="${D}" "${EPYTHON}" ./x.py install -vv --config="${S}"/config.toml -j$(makeopts_jobs) || die
+
+	# bug #689562, #689160
+	rm -v "${ED}/usr/lib/${PN}/${PV}/etc/bash_completion.d/cargo" || die
+	rmdir -v "${ED}/usr/lib/${PN}/${PV}"/etc{/bash_completion.d,} || die
+
+	local symlinks=(
+		cargo
+		rustc
+		rustdoc
+		rust-gdb
+		rust-gdbgui
+		rust-lldb
+		rust-demangler
+	)
+
+	use clippy && symlinks+=( clippy-driver cargo-clippy )
+	use miri && symlinks+=( miri cargo-miri )
+	use rustfmt && symlinks+=( rustfmt cargo-fmt )
+	use rust-analyzer && symlinks+=( rust-analyzer )
+
+	einfo "installing eselect-rust symlinks and paths: ${symlinks[@]}"
+	local i
+	for i in "${symlinks[@]}"; do
+		# we need realpath on /usr/bin/* symlink return version-appended binary path.
+		# so /usr/bin/rustc should point to /usr/lib/rust/<ver>/bin/rustc-<ver>
+		# need to fix eselect-rust to remove this hack.
+		local ver_i="${i}-${PV}"
+		if [[ -f "${ED}/usr/lib/${PN}/${PV}/bin/${i}" ]]; then
+			einfo "Installing ${i} symlink"
+			ln -v "${ED}/usr/lib/${PN}/${PV}/bin/${i}" "${ED}/usr/lib/${PN}/${PV}/bin/${ver_i}" || die
+		else
+			ewarn "${i} symlink requested, but source file not found"
+			ewarn "please report this"
+		fi
+		dosym "../lib/${PN}/${PV}/bin/${ver_i}" "/usr/bin/${ver_i}"
+	done
+
+	# symlinks to switch components to active rust in eselect
+	dosym "${PV}/lib" "/usr/lib/${PN}/lib-${PV}"
+	use rust-analyzer && dosym "${PV}/libexec" "/usr/lib/${PN}/libexec-${PV}"
+	dosym "${PV}/share/man" "/usr/lib/${PN}/man-${PV}"
+	dosym "rust/${PV}/lib/rustlib" "/usr/lib/rustlib-${PV}"
+	dosym "../../lib/${PN}/${PV}/share/doc/rust" "/usr/share/doc/${P}"
+
+	newenvd - "50${P}" <<-_EOF_
+		MANPATH="${EPREFIX}/usr/lib/rust/man-${PV}"
+	_EOF_
+
+	rm -rf "${ED}/usr/lib/${PN}/${PV}"/*.old || die
+	rm -rf "${ED}/usr/lib/${PN}/${PV}/bin"/*.old || die
+	rm -rf "${ED}/usr/lib/${PN}/${PV}/doc"/*.old || die
+
+	# note: eselect-rust adds EROOT to all paths below
+	cat <<-_EOF_ > "${T}/provider-${P}"
+		/usr/bin/cargo
+		/usr/bin/rustdoc
+		/usr/bin/rust-demangler
+		/usr/bin/rust-gdb
+		/usr/bin/rust-gdbgui
+		/usr/bin/rust-lldb
+		/usr/lib/rustlib
+		/usr/lib/rust/lib
+		/usr/lib/rust/man
+		/usr/share/doc/rust
+	_EOF_
+
+	if use clippy; then
+		echo /usr/bin/clippy-driver >> "${T}/provider-${P}"
+		echo /usr/bin/cargo-clippy >> "${T}/provider-${P}"
+	fi
+	if use miri; then
+		echo /usr/bin/miri >> "${T}/provider-${P}"
+		echo /usr/bin/cargo-miri >> "${T}/provider-${P}"
+	fi
+	if use rustfmt; then
+		echo /usr/bin/rustfmt >> "${T}/provider-${P}"
+		echo /usr/bin/cargo-fmt >> "${T}/pro