Add a test case for atomic ops

Make sure that the macros work properly with the range of types that
they are documented to work with and ensure that no strict aliasing
warnings are issued (even at the highest warning level).

https://bugzilla.gnome.org/show_bug.cgi?id=650935

glib/tests/.gitignore

@@ -1,4 +1,5 @@
 array-test
+atomic
 base64
 bookmarkfile
 checksum

glib/tests/Makefile.am

@@ -177,6 +177,10 @@ TEST_PROGS    += unix-nothreads
 unix_nothreads_SOURCES = unix.c
 unix_nothreads_LDADD  = $(progs_ldadd)
 
+noinst_PROGRAMS += atomic
+atomic_CFLAGS = -Wstrict-aliasing=2 $(INCLUDES)
+atomic_LDADD = $(progs_ldadd)
+
 # some testing of gtester funcitonality
 XMLLINT=xmllint
 gtester-xmllint-check: # check testreport xml with xmllint if present

glib/tests/atomic.c

@@ -0,0 +1,41 @@
+#include <glib.h>
+
+int
+main (void)
+{
+  guint u;
+  gint s;
+  gpointer vp;
+  int *ip;
+  gsize gs;
+
+  g_atomic_int_set (&u, 5);
+  g_atomic_int_get (&u);
+  g_atomic_int_compare_and_exchange (&u, 6, 7);
+  g_atomic_int_exchange_and_add (&u, 1);
+  g_atomic_int_add (&u, 1);
+  g_atomic_int_inc (&u);
+  (void) g_atomic_int_dec_and_test (&u);
+
+  g_atomic_int_set (&s, 5);
+  g_atomic_int_get (&s);
+  g_atomic_int_compare_and_exchange (&s, 6, 7);
+  g_atomic_int_exchange_and_add (&s, 1);
+  g_atomic_int_add (&s, 1);
+  g_atomic_int_inc (&s);
+  (void) g_atomic_int_dec_and_test (&s);
+
+  g_atomic_pointer_set (&vp, 0);
+  g_atomic_pointer_get (&vp);
+  g_atomic_pointer_compare_and_exchange (&vp, 0, 0);
+
+  g_atomic_pointer_set (&ip, 0);
+  g_atomic_pointer_get (&ip);
+  g_atomic_pointer_compare_and_exchange (&ip, 0, 0);
+
+  g_atomic_pointer_set (&gs, 0);
+  g_atomic_pointer_get (&gs);
+  g_atomic_pointer_compare_and_exchange (&gs, 0, 0);
+
+  return 0;
+}