qt6-build.eclass: extend -m* flags sanitizing

A user on the forums reported a build failure with:
`-march=znver4 -mavx512vp2intersect`

On its own, there is no issue there (expanded from -march=native) but
when Qt passes `-march=haswell` to build certain parts (e.g. avx2 bits
for runtime detection regardless of what CHOST supports), it overrides
znver4 and keeps -mavx512vp2intersect resulting in an incomplete set
and then qsimd_p.h complains

Do not plan to pursue this myself, but this specific issue could
be improved upstream by passing -mavx2 and others rather than
-march=haswell (this would also allow overriding a -mno-avx2 that
we currently need to change), and/or ideally by making qsimd_p.h
be able to deal with these configurations without #error.

If problems keep piling up, could consider always filtering *all*
-m{,no-}<instr> flags and doing x86-64-v* unconditionally. Albeit
that'd still require maintaining a list of these not to filter
unrelated -m* flags which could be important.

Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

0 files changed, 0 insertions, 0 deletions