include errno.h
diff --git a/src/hb-blob.c b/src/hb-blob.c
index 377310e..60982f8 100644
--- a/src/hb-blob.c
+++ b/src/hb-blob.c
@@ -41,6 +41,7 @@
 
 #if HB_DEBUG_BLOB
 #include <stdio.h>
+#include <errno.h>
 #endif
 
 struct _hb_blob_t {