New upstream version 1.4.0+dfsgupstream/1.4.0+dfsg

1 files changed, 30 insertions, 0 deletions

diff --git a/m4/ax_c___atomic.m4 b/m4/ax_c___atomic.m4
new file mode 100644
index 000000000..131929ae1
--- /dev/null
+++ b/m4/ax_c___atomic.m4
@@ -0,0 +1,30 @@
+# AC_C___ATOMIC
+# -------------
+# Define HAVE_C___ATOMIC if __atomic works.
+AN_IDENTIFIER([__atomic], [AC_C___ATOMIC])
+AC_DEFUN([AC_C___ATOMIC],
+[AC_CACHE_CHECK([for __atomic], ac_cv_c___atomic,
+[AC_LINK_IFELSE(
+   [AC_LANG_SOURCE(
+      [[int
+        main (int argc, char **argv)
+        {
+          volatile unsigned long ul1 = 1, ul2 = 0, ul3 = 2;
+          __atomic_compare_exchange(&ul1, &ul2, &ul3, 1, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+          __atomic_fetch_add(&ul1, 1, __ATOMIC_SEQ_CST);
+          __atomic_fetch_sub(&ul3, 1, __ATOMIC_SEQ_CST);
+          volatile unsigned long long ull1 = 1, ull2 = 0, ull3 = 2;
+          __atomic_compare_exchange(&ull1, &ull2, &ull3, 1, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
+          __atomic_fetch_add(&ull1, 1, __ATOMIC_SEQ_CST);
+          __atomic_fetch_sub(&ull3, 1, __ATOMIC_SEQ_CST);
+          return 0;
+        }
+      ]])],
+   [ac_cv_c___atomic=yes],
+   [ac_cv_c___atomic=no])])
+if test $ac_cv_c___atomic = yes; then
+  AC_DEFINE([HAVE_C___ATOMIC], 1,
+           [Define to 1 if __atomic operations work.])
+fi
+])# AC_C___ATOMIC
+