[HB] Put C++ inline's back

Apparetly in C++, inline means a totally different thing.
diff --git a/src/hb-ot-layout-gsubgpos-private.hh b/src/hb-ot-layout-gsubgpos-private.hh
index c322dfb..559ee08 100644
--- a/src/hb-ot-layout-gsubgpos-private.hh
+++ b/src/hb-ot-layout-gsubgpos-private.hh
@@ -439,7 +439,7 @@
 struct Context
 {
   protected:
-  bool apply (APPLY_ARG_DEF, apply_lookup_func_t apply_func) const
+  inline bool apply (APPLY_ARG_DEF, apply_lookup_func_t apply_func) const
   {
     switch (u.format) {
     case 1: return u.format1->apply (APPLY_ARG, apply_func);
@@ -449,7 +449,7 @@
     }
   }
 
-  bool sanitize (SANITIZE_ARG_DEF) {
+  inline bool sanitize (SANITIZE_ARG_DEF) {
     SANITIZE_DEBUG ();
     if (!SANITIZE (u.format)) return false;
     switch (u.format) {
@@ -746,7 +746,7 @@
 struct ChainContext
 {
   protected:
-  bool apply (APPLY_ARG_DEF, apply_lookup_func_t apply_func) const
+  inline bool apply (APPLY_ARG_DEF, apply_lookup_func_t apply_func) const
   {
     switch (u.format) {
     case 1: return u.format1->apply (APPLY_ARG, apply_func);
@@ -756,7 +756,7 @@
     }
   }
 
-  bool sanitize (SANITIZE_ARG_DEF) {
+  inline bool sanitize (SANITIZE_ARG_DEF) {
     SANITIZE_DEBUG ();
     if (!SANITIZE (u.format)) return false;
     switch (u.format) {
@@ -826,7 +826,7 @@
     }
   }
 
-  bool sanitize (SANITIZE_ARG_DEF) {
+  inline bool sanitize (SANITIZE_ARG_DEF) {
     SANITIZE_DEBUG ();
     if (!SANITIZE (u.format)) return false;
     switch (u.format) {
@@ -884,7 +884,7 @@
   inline const Lookup& get_lookup (unsigned int i) const
   { return (this+lookupList)[i]; }
 
-  bool sanitize (SANITIZE_ARG_DEF) {
+  inline bool sanitize (SANITIZE_ARG_DEF) {
     SANITIZE_DEBUG ();
     if (!SANITIZE (version)) return false;
     if (version.major != 1) return true;