diff --git a/src/hb-common.h b/src/hb-common.h
index d404353..1cdbd5e 100644
--- a/src/hb-common.h
+++ b/src/hb-common.h
@@ -30,11 +30,11 @@
 #include <stdint.h>
 
 # ifdef __cplusplus
-#  define HB_BEGIN_DECLS() extern "C" { extern int hb_dummy_prototype (int)
-#  define HB_END_DECLS() } extern "C" int hb_dummy_prototype (int)
+#  define HB_BEGIN_DECLS() extern "C" { extern int _hb_dummy_prototype1 (int)
+#  define HB_END_DECLS() } extern "C" int _hb_dummy_prototype2 (int)
 # else /* !__cplusplus */
-#  define HB_BEGIN_DECLS()   extern int hb_dummy_prototype (int)
-#  define HB_END_DECLS()     extern int hb_dummy_prototype (int)
+#  define HB_BEGIN_DECLS()   extern int _hb_dummy_prototype1 (int)
+#  define HB_END_DECLS()     extern int _hb_dummy_prototype2 (int)
 # endif /* !__cplusplus */
 
 typedef int hb_bool_t;
@@ -47,8 +47,7 @@
 				((const char *) s)[3]))
 
 typedef uint32_t hb_codepoint_t;
-
-/* XXX */
-typedef struct HB_BufferRec_ hb_buffer_t;
+typedef int32_t hb_position_t;
+typedef int32_t hb_16dot16_t;
 
 #endif /* HB_COMMON_H */