include stdint.h for int32_t/uint32_t

Signed-off-by: Jussi Kukkonen <jussi.kukkonen@intel.com>
Reviewed-by: Yong Bakos <ybakos@humanoriented.com>
diff --git a/libweston/spring-tool.c b/libweston/spring-tool.c
index 1848b3f..9e7c344 100644
--- a/libweston/spring-tool.c
+++ b/libweston/spring-tool.c
@@ -23,6 +23,8 @@
  * SOFTWARE.
  */
 
+#include <stdint.h>
+
 #include "config.h"
 
 #include "compositor.h"