Add the ability to have formally deprecated functions.

Functions which are deprecated will print out a message and show up in a small dialog on-screen, when they're first called. Deprecation output is disabled in fused mode by default, and can be modified with love.setDeprecationOutput(enable).

--HG--
branch : minor

src/common/runtime.h

@@ -23,6 +23,7 @@
 
 // LOVE
 #include "types.h"
+#include "deprecation.h"
 
 // Lua
 extern "C" {
@@ -447,6 +448,13 @@ lua_State *luax_insistpinnedthread(lua_State *L);
  **/
 lua_State *luax_getpinnedthread(lua_State *L);
 
+/**
+ * Mark a function as deprecated. Should only be called inside wrapper function
+ * code.
+ **/
+void luax_markdeprecated(lua_State *L, const char *name);
+void luax_markdeprecated(lua_State *L, const char *name, DeprecationType type, const char *replacement);
+
 extern "C" { // Also called from luasocket
 	int luax_typerror(lua_State *L, int narg, const char *tname);
 }