Prefer C linkage
diff --git a/src/hb-common.c b/src/hb-common.c
index d205fc8..74f8933 100644
--- a/src/hb-common.c
+++ b/src/hb-common.c
@@ -26,6 +26,9 @@
 
 #include "hb-private.h"
 
+HB_BEGIN_DECLS
+
+
 hb_tag_t
 hb_tag_from_string (const char *s)
 {
@@ -39,3 +42,6 @@
 
   return HB_TAG_STR (tag);
 }
+
+
+HB_END_DECLS