__builtin_add_overflow  112 lib/intprops-internal.h # define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow)
__builtin_add_overflow  152 lib/intprops-internal.h # define _GL_INT_ADD_WRAPV(a, b, r) __builtin_add_overflow (a, b, r)