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)