Index: boot/generic/include/gzip.h
===================================================================
--- boot/generic/include/gzip.h	(revision 28a5ebdea900783081bd23e40f685b6b0479c63d)
+++ boot/generic/include/gzip.h	(revision 5fc82448bbd01f2950b893989095ed4c1b1c99b3)
@@ -30,6 +30,9 @@
 #define LIBCOMPRESS_GZIP_H_
 
+#include <stdbool.h>
 #include <stddef.h>
-size_t gzip_size(const void *, size_t);
+
+extern bool gzip_check(const void *, size_t);
+extern size_t gzip_size(const void *, size_t);
 extern int gzip_expand(const void *, size_t, void *, size_t);