diff --git a/src/hb-ot-layout-common-private.hh b/src/hb-ot-layout-common-private.hh
index ea61f5c1bd5f872e5794b71f89e3ae8661549a82..84a163575c4353db4d50e9d21c1efaf3a48b6611 100644
--- a/src/hb-ot-layout-common-private.hh
+++ b/src/hb-ot-layout-common-private.hh
@@ -34,6 +34,14 @@
 #include "hb-set-private.hh"
 
 
+#ifndef HB_MAX_NESTING_LEVEL
+#define HB_MAX_NESTING_LEVEL	6
+#endif
+#ifndef HB_MAX_CONTEXT_LENGTH
+#define HB_MAX_CONTEXT_LENGTH	64
+#endif
+
+
 namespace OT {
 
 
@@ -44,8 +52,6 @@ namespace OT {
 
 
 #define NOT_COVERED		((unsigned int) -1)
-#define MAX_NESTING_LEVEL	6
-#define MAX_CONTEXT_LENGTH	64
 
 
 
diff --git a/src/hb-ot-layout-gsub-table.hh b/src/hb-ot-layout-gsub-table.hh
index eebc87b4c59caa416f2c796f020a389cff430c36..459a1a3dd5c49608f3b3fc892f366fe828320ead 100644
--- a/src/hb-ot-layout-gsub-table.hh
+++ b/src/hb-ot-layout-gsub-table.hh
@@ -630,7 +630,7 @@ struct Ligature
     unsigned int total_component_count = 0;
 
     unsigned int match_length = 0;
-    unsigned int match_positions[MAX_CONTEXT_LENGTH];
+    unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
 
     if (likely (!match_input (c, count,
 			      &component[1],
@@ -970,7 +970,7 @@ struct ReverseChainSingleSubstFormat1
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
-    if (unlikely (c->nesting_level_left != MAX_NESTING_LEVEL))
+    if (unlikely (c->nesting_level_left != HB_MAX_NESTING_LEVEL))
       return_trace (false); /* No chaining to this type */
 
     unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index 230b3b6851bd209ae9684e355e4502686bcc371b..fb411db1132d06dd7823ed96baf9a94195069f8f 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -74,7 +74,7 @@ struct hb_closure_context_t :
 
   hb_closure_context_t (hb_face_t *face_,
 			hb_set_t *glyphs_,
-		        unsigned int nesting_level_left_ = MAX_NESTING_LEVEL) :
+		        unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :
 			  face (face_),
 			  glyphs (glyphs_),
 			  recurse_func (NULL),
@@ -196,7 +196,7 @@ struct hb_collect_glyphs_context_t :
 			       hb_set_t  *glyphs_input,  /* OUT. May be NULL */
 			       hb_set_t  *glyphs_after,  /* OUT. May be NULL */
 			       hb_set_t  *glyphs_output, /* OUT. May be NULL */
-			       unsigned int nesting_level_left_ = MAX_NESTING_LEVEL) :
+			       unsigned int nesting_level_left_ = HB_MAX_NESTING_LEVEL) :
 			      face (face_),
 			      before (glyphs_before ? glyphs_before : hb_set_get_empty ()),
 			      input  (glyphs_input  ? glyphs_input  : hb_set_get_empty ()),
@@ -483,7 +483,7 @@ struct hb_apply_context_t :
 			lookup_mask (1),
 			auto_zwj (true),
 			recurse_func (NULL),
-			nesting_level_left (MAX_NESTING_LEVEL),
+			nesting_level_left (HB_MAX_NESTING_LEVEL),
 			lookup_props (0),
 			gdef (*hb_ot_layout_from_face (face)->gdef),
 			has_glyph_classes (gdef.has_glyph_classes ()),
@@ -704,13 +704,13 @@ static inline bool match_input (hb_apply_context_t *c,
 				match_func_t match_func,
 				const void *match_data,
 				unsigned int *end_offset,
-				unsigned int match_positions[MAX_CONTEXT_LENGTH],
+				unsigned int match_positions[HB_MAX_CONTEXT_LENGTH],
 				bool *p_is_mark_ligature = NULL,
 				unsigned int *p_total_component_count = NULL)
 {
   TRACE_APPLY (NULL);
 
-  if (unlikely (count > MAX_CONTEXT_LENGTH)) return_trace (false);
+  if (unlikely (count > HB_MAX_CONTEXT_LENGTH)) return_trace (false);
 
   hb_buffer_t *buffer = c->buffer;
 
@@ -784,7 +784,7 @@ static inline bool match_input (hb_apply_context_t *c,
 }
 static inline bool ligate_input (hb_apply_context_t *c,
 				 unsigned int count, /* Including the first glyph */
-				 unsigned int match_positions[MAX_CONTEXT_LENGTH], /* Including the first glyph */
+				 unsigned int match_positions[HB_MAX_CONTEXT_LENGTH], /* Including the first glyph */
 				 unsigned int match_length,
 				 hb_codepoint_t lig_glyph,
 				 bool is_mark_ligature,
@@ -944,7 +944,7 @@ static inline void recurse_lookups (context_t *c,
 
 static inline bool apply_lookup (hb_apply_context_t *c,
 				 unsigned int count, /* Including the first glyph */
-				 unsigned int match_positions[MAX_CONTEXT_LENGTH], /* Including the first glyph */
+				 unsigned int match_positions[HB_MAX_CONTEXT_LENGTH], /* Including the first glyph */
 				 unsigned int lookupCount,
 				 const LookupRecord lookupRecord[], /* Array of LookupRecords--in design order */
 				 unsigned int match_length)
@@ -995,7 +995,7 @@ static inline bool apply_lookup (hb_apply_context_t *c,
 
     if (delta > 0)
     {
-      if (unlikely (delta + count > MAX_CONTEXT_LENGTH))
+      if (unlikely (delta + count > HB_MAX_CONTEXT_LENGTH))
 	break;
     }
     else
@@ -1094,7 +1094,7 @@ static inline bool context_apply_lookup (hb_apply_context_t *c,
 					 ContextApplyLookupContext &lookup_context)
 {
   unsigned int match_length = 0;
-  unsigned int match_positions[MAX_CONTEXT_LENGTH];
+  unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
   return match_input (c,
 		      inputCount, input,
 		      lookup_context.funcs.match, lookup_context.match_data,
@@ -1621,7 +1621,7 @@ static inline bool chain_context_apply_lookup (hb_apply_context_t *c,
 					       ChainContextApplyLookupContext &lookup_context)
 {
   unsigned int match_length = 0;
-  unsigned int match_positions[MAX_CONTEXT_LENGTH];
+  unsigned int match_positions[HB_MAX_CONTEXT_LENGTH];
   return match_input (c,
 		      inputCount, input,
 		      lookup_context.funcs.match, lookup_context.match_data[1],