gobject: don't use G_STRLOC in G_OBJECT_WARN_INVALID_PSPEC() macro

Using G_STRLOC ends up embedding unique strings of the form
__FILE__:__LINE__ in the compiled binary. We can avoid these
by passing __FILE__ and __LINE__ separately when constructing
the warning text.
This probably reduces the size of the binary as __FILE__ is
likely already contained as string otherwise.

Note that for GCC 2.x this changes behavior because G_STRLOC
also contained __PRETTY_FUNCTION__.

https://bugzilla.gnome.org/show_bug.cgi?id=741654

gobject/gobject.h

@@ -627,8 +627,8 @@ G_STMT_START { \
   GObject *_glib__object = (GObject*) (object); \
   GParamSpec *_glib__pspec = (GParamSpec*) (pspec); \
   guint _glib__property_id = (property_id); \
-  g_warning ("%s: invalid %s id %u for \"%s\" of type '%s' in '%s'", \
-             G_STRLOC, \
+  g_warning ("%s:%u: invalid %s id %u for \"%s\" of type '%s' in '%s'", \
+             __FILE__, __LINE__, \
              (pname), \
              _glib__property_id, \
              _glib__pspec->name, \