701eb26f97
Oracle Linux 7 sets __STDC_VERSION__ to 201112L, but doesn't define __STDC_NO_ATOMICS__, so we try to include <stdatomic.h> without the header present in the system. Since we are already detecting the header in the autoconf, use the HAVE_STDATOMIC_H for more reliable detecting whether <stdatomic.h> header is present.