ObjFW  Diff

				AC_MSG_RESULT(no)
			])
		])
	])

	atomic_ops="none"

	AC_MSG_CHECKING(whether __sync_* works)
	AC_TRY_LINK([#include <stdint.h>], [
		int32_t i, j;
		if (__sync_add_and_fetch(&i, 1))
			j = __sync_sub_and_fetch(&i, 1);
		while (!__sync_bool_compare_and_swap(&i, 0, 1));
	], [
		AC_MSG_RESULT(yes)
		atomic_ops="GCC builtins"
		AC_DEFINE(OF_HAVE_GCC_ATOMIC_OPS, 1,
			[Whether GCC atomic operations are available])
	], [
		AC_MSG_RESULT(no)
	])

	AC_MSG_CHECKING(whether we have an atomic ops assembly implementation)
	AC_EGREP_CPP(yes, [
		#if defined(__GNUC__) && (defined(__i386__) || \
			defined(__x86_64__) || defined(__amd64__)) || \
			defined(__ppc__)
		yes
		#endif
	], [
		AC_MSG_RESULT(yes)
		atomic_ops="assembly implementation"
	], [
		AC_MSG_RESULT(no)
	])

	AC_MSG_CHECKING(whether __sync_* works)
	AC_TRY_LINK([#include <stdint.h>], [
		int32_t i, j;
		if (__sync_add_and_fetch(&i, 1))
			j = __sync_sub_and_fetch(&i, 1);
		while (!__sync_bool_compare_and_swap(&i, 0, 1));
	], [
		AC_MSG_RESULT(yes)
		test x"$atomic_ops" = x"none" && \
			atomic_ops="assembly implementation"
			atomic_ops="__sync_* builtins"
		AC_DEFINE(OF_HAVE_SYNC_BUILTINS, 1,
			[Whether __sync_* builtins are available])
	], [
		AC_MSG_RESULT(no)
	])

	AC_CHECK_HEADER(libkern/OSAtomic.h, [
		test x"$atomic_ops" = x"none" && atomic_ops="libkern/OSAtomic.h"
		AC_DEFINE(OF_HAVE_OSATOMIC, 1,