build: Remove unused AX_CHECK_COMPILE_FLAG macro

Unused since 1a6ae840413d7fb6d2e83f6a83081d5246c7ac9e

Signed-off-by: Andreas Boll <andreas.boll.dev@gmail.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
1 file changed