--- a/configure.in	Mon Jul 06 21:48:52 2009 +0000
+++ b/configure.in	Mon Jul 06 21:56:38 2009 +0000
@@ -2881,6 +2881,12 @@
             SOURCES="$SOURCES $srcdir/src/audio/macrom/*.c"
             have_audio=yes
         fi
+        # Set up files for the atomic operations library
+        if test x$enable_atomic = xyes; then
+            AC_DEFINE(SDL_ATOMIC_MACOSX)
+            SOURCES="$SOURCES $srcdir/src/atomic/macosx/*.c"
+            have_atomic=yes
+        fi
         # Set up files for the joystick library
         if test x$enable_joystick = xyes; then
             AC_DEFINE(SDL_JOYSTICK_IOKIT)