Annex C (informative) Compatibility [diff]

C.6 C standard library [diff.library]

C.6.3 Modifications to definitions [diff.mods.to.definitions]

C.6.3.5 Header <stdalign.h> [diff.header.stdalign.h]

The token alignas is a keyword in C++ ([lex.key]), and is not introduced as a macro by <stdalign.h>.