schema tree FEATURE features and if-features compilation and handling functions
diff --git a/src/common.h b/src/common.h
index a214f4d..380ec6e 100644
--- a/src/common.h
+++ b/src/common.h
@@ -15,6 +15,7 @@
 #ifndef LY_COMMON_H_
 #define LY_COMMON_H_
 
+#include <assert.h>
 #include <stdint.h>
 #include <stdlib.h>