fix various GCC function pointer warnings
diff --git a/src/hb-debug.hh b/src/hb-debug.hh
index 58c190d..d218e43 100644
--- a/src/hb-debug.hh
+++ b/src/hb-debug.hh
@@ -173,7 +173,7 @@
fprintf (stderr, "\n");
}
-template <> inline void
+template <> inline void HB_PRINTF_FUNC(7, 0)
_hb_debug_msg_va<0> (const char *what HB_UNUSED,
const void *obj HB_UNUSED,
const char *func HB_UNUSED,
@@ -192,7 +192,7 @@
int level_dir,
const char *message,
...) HB_PRINTF_FUNC(7, 8);
-template <int max_level> static inline void
+template <int max_level> static inline void HB_PRINTF_FUNC(7, 8)
_hb_debug_msg (const char *what,
const void *obj,
const char *func,
@@ -216,7 +216,7 @@
int level_dir HB_UNUSED,
const char *message HB_UNUSED,
...) HB_PRINTF_FUNC(7, 8);
-template <> inline void
+template <> inline void HB_PRINTF_FUNC(7, 8)
_hb_debug_msg<0> (const char *what HB_UNUSED,
const void *obj HB_UNUSED,
const char *func HB_UNUSED,
