ObjFW  Diff

	AC_CHECK_FUNC(objc_sync_enter,, [
		AC_SUBST(OBJC_SYNC_M, "objc_sync.m")
		AC_DEFINE(NEED_OBJC_SYNC_INIT, 1,
			[Whether objc_sync_init needs to be called])])

	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_CHECKING(whether we have an atomic ops assembly implementation)
	AC_EGREP_CPP(yes, [
		#if defined(__GNUC__) && (defined(__i386__) || \
		    defined(__amd64__) || defined(__x86_64__))
		yes
		#endif
		], [
		AC_MSG_RESULT(yes)
		atomic_ops="gcc builtins"
		atomic_ops="assembly implementation"
		AC_DEFINE(OF_HAVE_GCC_ATOMIC_OPS, 1,
			[Whether gcc atomic operations are available])
		], [
		old_OBJCFLAGS="$OBJCFLAGS"
		], [AC_MSG_RESULT(no)])

		OBJCFLAGS="$OBJCFLAGS -march=i486"
	if test x"$atomic_ops" = x"none"; then
		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, with -march=i486])
			atomic_ops="gcc builtins (with -march=i486)"
			AC_MSG_RESULT(yes)
			atomic_ops="gcc builtins"
			AC_DEFINE(OF_HAVE_GCC_ATOMIC_OPS, 1,
				[Whether gcc atomic operations are available])
			AC_SUBST(ATOMIC_OBJCFLAGS, "-march=i486")
			], [
			AC_MSG_RESULT(no)
			], [AC_MSG_RESULT(no)])
			OBJCFLAGS="$old_OBJCFLAGS"])])
	fi

	if test x"$atomic_ops" = x"none"; then
		AC_CHECK_HEADER(libkern/OSAtomic.h, [
			atomic_ops="libkern/OSAtomic.h"
			AC_DEFINE(OF_HAVE_LIBKERN_OSATOMIC_H, 1,
				[Whether we have libkern/OSAtomic.h])])
	fi