Fix warnings

src/hb-open-type-private.hh

diff --git a/src/hb-open-type-private.hh b/src/hb-open-type-private.hh
index 9977a6e..36e565f 100644
--- a/src/hb-open-type-private.hh
+++ b/src/hb-open-type-private.hh
@@ -118,7 +118,7 @@
 
 #if HB_DEBUG_SANITIZE
 #include <stdio.h>
-#define TRACE_SANITIZE_ARG_DEF	, unsigned int sanitize_depth
+#define TRACE_SANITIZE_ARG_DEF	, unsigned int sanitize_depth HB_GNUC_UNUSED
 #define TRACE_SANITIZE_ARG	, sanitize_depth + 1
 #define TRACE_SANITIZE_ARG_INIT	, 1
 #define TRACE_SANITIZE() \

src/hb-ot-layout-gdef-private.hh

diff --git a/src/hb-ot-layout-gdef-private.hh b/src/hb-ot-layout-gdef-private.hh
index a047cb2..d9b0005 100644
--- a/src/hb-ot-layout-gdef-private.hh
+++ b/src/hb-ot-layout-gdef-private.hh
@@ -133,7 +133,7 @@
 {
   friend struct CaretValue;
 
-  inline int get_caret_value (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id) const
+  inline int get_caret_value (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id HB_GNUC_UNUSED) const
   {
     /* TODO vertical */
     return context->font->x_scale * coordinate / 0x10000 +

src/hb-ot-layout-gpos-private.hh

diff --git a/src/hb-ot-layout-gpos-private.hh b/src/hb-ot-layout-gpos-private.hh
index 08f8151..e72e7b3 100644
--- a/src/hb-ot-layout-gpos-private.hh
+++ b/src/hb-ot-layout-gpos-private.hh
@@ -133,7 +133,7 @@
   friend struct Anchor;
 
   private:
-  inline void get_anchor (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id,
+  inline void get_anchor (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id HB_GNUC_UNUSED,
 			  hb_position_t *x, hb_position_t *y) const
   {
       *x = _hb_16dot16_mul_trunc (context->font->x_scale, xCoordinate);
@@ -184,7 +184,7 @@
   friend struct Anchor;
 
   private:
-  inline void get_anchor (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id,
+  inline void get_anchor (hb_ot_layout_context_t *context, hb_codepoint_t glyph_id HB_GNUC_UNUSED,
 			  hb_position_t *x, hb_position_t *y) const
   {
       *x = _hb_16dot16_mul_trunc (context->font->x_scale, xCoordinate);

src/hb-ot-layout-gsubgpos-private.hh

diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 4561aa3..ee9db67 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -37,7 +37,7 @@
 
 #if HB_DEBUG_APPLY
 #include <stdio.h>
-#define TRACE_APPLY_ARG_DEF	, unsigned int apply_depth
+#define TRACE_APPLY_ARG_DEF	, unsigned int apply_depth HB_GNUC_UNUSED
 #define TRACE_APPLY_ARG		, apply_depth + 1
 #define TRACE_APPLY_ARG_INIT	, 1
 #define TRACE_APPLY() \
@@ -60,7 +60,7 @@
 	hb_buffer_t    *buffer, \
 	unsigned int    context_length HB_GNUC_UNUSED, \
 	unsigned int    nesting_level_left HB_GNUC_UNUSED, \
-	unsigned int    lookup_flag, \
+	unsigned int    lookup_flag HB_GNUC_UNUSED, \
 	unsigned int    property HB_GNUC_UNUSED /* propety of first glyph */ \
 	TRACE_APPLY_ARG_DEF
 #define APPLY_ARG \
@@ -91,7 +91,7 @@
 };
 
 
-static inline bool match_glyph (hb_codepoint_t glyph_id, const USHORT &value, char *data)
+static inline bool match_glyph (hb_codepoint_t glyph_id, const USHORT &value, char *data HB_GNUC_UNUSED)
 {
   return glyph_id == value;
 }