ImportC: alignment value expected, not `_Alignof`

[drpriver]

Following C code (found in some system headers on macOS) fails to parse with importC:

#define _STRUCT_ARM_SVE_Z_STATE struct arm_sve_z_state
_STRUCT_ARM_SVE_Z_STATE
{
	char            z[16][256];
} __attribute__((aligned(_Alignof(unsigned int))));

Fails with "alignment value expected, not _Alignof”.

Unfortunately, this clang attribute is not documented: https://clang.llvm.org/docs/AttributeReference.html#alignas-align-alignas-aligned

but I imagine it should be able to take anything that evaluates to a compile-time constant integer expression.

Why they couldn’t use a standards-compliant solution I don’t know...

[drpriver]

Testing shows GCC also supports this syntax.

[drpriver]

GCC docs for aligned here: https://gcc.gnu.org/onlinedocs/gcc/Common-Type-Attributes.html#index-aligned-type-attribute

Doesn’t document what the argument to aligned is allowed to be, but both compilers apparently support the example.