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/animation.c b/libweston/animation.c
index 2c7943f..30b3e5d 100644
--- a/libweston/animation.c
+++ b/libweston/animation.c
@@ -27,6 +27,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <math.h>