diff --git a/build/aclocal/atomic_builtins.m4 b/build/aclocal/atomic_builtins.m4
index 8366eb3ef4..eac5d3336a 100644
--- a/build/aclocal/atomic_builtins.m4
+++ b/build/aclocal/atomic_builtins.m4
@@ -16,7 +16,7 @@ AC_DEFUN([WX_ATOMIC_BUILTINS],
           __sync_fetch_and_add(&value, 2);
           __sync_sub_and_fetch(&value, 1);
           /* but wxAtomicDec does, so mimic that: */
-          unsigned int r2 = __sync_sub_and_fetch(&value, 1);
+          volatile unsigned int r2 = __sync_sub_and_fetch(&value, 1);
         ],
         wx_cv_cc_gcc_atomic_builtins=yes,
         wx_cv_cc_gcc_atomic_builtins=no)
diff --git a/configure b/configure
index 7697a87f25..c922d7ee61 100755
--- a/configure
+++ b/configure
@@ -21867,7 +21867,7 @@ main ()
           __sync_fetch_and_add(&value, 2);
           __sync_sub_and_fetch(&value, 1);
           /* but wxAtomicDec does, so mimic that: */
-          unsigned int r2 = __sync_sub_and_fetch(&value, 1);
+          volatile unsigned int r2 = __sync_sub_and_fetch(&value, 1);
 
   ;
   return 0;