configure.ac: test for the same atomic function as the one we use

Unlikely that we'll hit a case where __sync_fetch_and_add is present
while __sync_add_and_fetch isn't. Regardless let's keep things sane and
consistent.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

diff --git a/configure.ac b/configure.ac
index 89a3a46..b929d36 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -210,7 +210,7 @@ AC_CACHE_CHECK([for native atomic primitives], drm_cv_atomic_primitives, [
        drm_cv_atomic_primitives="none"
 
        AC_LINK_IFELSE([AC_LANG_PROGRAM([[
-       int atomic_add(int *i) { return __sync_fetch_and_add (i, 1); }
+       int atomic_add(int *i) { return __sync_add_and_fetch (i, 1); }
        int atomic_cmpxchg(int *i, int j, int k) { return __sync_val_compare_and_swap (i, j, k); }
                                          ]],[[]])], [drm_cv_atomic_primitives="Intel"],[])