Since GCC 4.9 doesn't have __builtin_add_overflow:
In file included from tst-stringtable.c:180:0:
stringtable.c: In function ‘stringtable_finalize’:
stringtable.c:185:7: error: implicit declaration of function ‘__builtin_add_overflow’ [-Werror=implicit-function-declaration]
else if (__builtin_add_overflow (previous->offset,
^
return EXIT_UNSUPPORTED for GCC 4.9 or older.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>