Remove dependency to CPP: added pre-defined macros

A number of macros are pre-defined by WindowMaker for CPP in the
function 'MakeCPPArgs', they are now available in the internal
parser too. CPP also had some predefined macros, a subset of them
have been added.
The definition have been split in two parts:
 - the macro that are dependant on WindowMaker parameters are
defined by WindowMaker (src/rootmenu.c)
 - those that are independant, which can be defined by the parser
itself (WINGs/menuparser_macros.c)

WINGs/menuparser.c

@@ -42,6 +42,7 @@ WMenuParser WMenuParserCreate(const char *file_name, void *file,
 	WMenuParser parser;
 
 	parser = menu_parser_create_new(file_name, file, include_default_paths);
+	menu_parser_register_preset_macros(parser);
 	return parser;
 }