-mattr=+feature should be propagated in the dflags

[MrcSnm]

Those bugs are silently breaking packages which depends on ldc features.
That same issue also happens when one uses -checkaction=

AuburnSounds/intel-intrinsics#152
AuburnSounds/intel-intrinsics#143

The current solution is to use --combined which most people don't write for no reason

[p0nce]

My best guess is that when compiled with -mattr=+avx a function returns a 256-bit vector in YMM0, and without in XMM0 and XMM1. Leading to ABI differences.

[p0nce]

Here is a repro DUB project.

repro2.zip

You can see the library is built without -mattr=+avx but the executable is built with -mattr=+avx