❯ $CXX -dM -E test.cc | rg ALIGN 
#define _GLIBCXX_HAVE_STDALIGN_H 1
#define _GLIBCXX_HAVE_MEMALIGN 1
#define _GLIBCXX_HAVE_POSIX_MEMALIGN 1
#define __BIGGEST_ALIGNMENT__ 16
#define _GLIBCXX_HAVE_ALIGNED_ALLOC 1