_GL_HAS_BUILTIN_MUL_OVERFLOW  116 lib/intprops-internal.h #    define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
_GL_HAS_BUILTIN_MUL_OVERFLOW  118 lib/intprops-internal.h #    define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW