re PR preprocessor/12847 (xxx.c:1:20: xxxx.h: No such file or directory)

re PR preprocessor/12847 (xxx.c:1:20: xxxx.h: No such file or directory)

	PR preprocessor/12847
	* cppfiles.c, cppexp.c, cpperror.c, cpplib.h, cpplib.c, cpplex.c,
	cppinit.c, cpptrad.c, cppmacro.c, fix-header.c, cpppch.c, c-pch.c,
	c-incpath.c, cppcharset.c (DL_WARNING, DL_WARNING_SYSHDR, DL_PEDWARN,
	DL_ERROR, DL_ICE, DL_EXTRACT, DL_WARNING_P): Prefix macro names with
	"CPP_".

From-SVN: r73183