add a useful common header with common function/define

Signed-off-by: Julien Danjou <[email protected]>

xcb-util-common.h

@@ -0,0 +1,33 @@
+/*
+ * Common useful header for xcb-util
+ *
+ * Copyright © 2009 Julien Danjou <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
+ * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Except as contained in this notice, the names of the authors or
+ * their institutions shall not be used in advertising or otherwise to
+ * promote the sale, use or other dealings in this Software without
+ * prior written authorization from the authors.
+ *
+ */
+
+#define ssizeof(foo)            (ssize_t)sizeof(foo)
+#define countof(foo)            (ssizeof(foo) / ssizeof(foo[0]))