Fix luasocket compatibility with luajit 2.1.0 beta 3 (fix #1277)

Note that luasocket 3.0 (in minor) targets lua 5.1, so it does not rely on a
5.0 compatibility feature, and does not require this patch. Since a 0.10.3
release seems unlikely at this point, this commit is mostly targeted at future
packagers of older love versions.

changes.txt

@@ -8,6 +8,7 @@ Released: N/A
   * Fixed Shader:send and Shader:sendColor ignoring the last argument for an array.
   * Fixed a crash when love.graphics.pop is called after a love.window.setMode while the transformation stack was not empty.
   * Fixed BezierCurves to error instead of hanging in some situations.
+  * Fixed compilation of luasocket with newer luajit 2.1.0 beta versions.
 
   * Improved command line argument handling.
   * Improved seeking support, especially for short video files.

src/libraries/luasocket/libluasocket/lua.h

@@ -6,9 +6,12 @@
 #include <lualib.h>
 #include <lauxlib.h>
 
-#if LUA_VERSION_NUM > 501
+#if LUA_VERSION_NUM >= 501
+#	undef luaL_reg
 #	define luaL_reg luaL_Reg
+#	undef luaL_putchar
 #	define luaL_putchar(B, c) luaL_addchar(B, c)
+#	undef luaL_typerror
 #	define luaL_typerror(L, n, t) luax_typerror(L, n, t)
 
 extern int luax_typerror(lua_State *L, int narg, const char *type);