More build fixes. Changed the documentation builder to automatically prepend %EPOCROOT% (converted to a path relative form) to pre-processor include path options that start with 'epoc32'. Prevously $(EPOCROOT) was prepended in the makefile, which broke the documentation build because the pre-processor will only accecpt relative path include options.

EXPORTS
	?ImplementationGroupProxy@@YAPBUTImplementationProxy@@AAH@Z @ 1 NONAME ; struct TImplementationProxy const * ImplementationGroupProxy(int &)
	?KAutoStartFshell@@3HB @ 2 NONAME ; int const KAutoStartFshell