<cctype>: Do we still need to defend against isalnum/etc. macros?

[StephanTLavavej]

STL/stl/inc/cctype

Lines 21 to 35 in d0d724f

	// remove any (improper) macro overrides
	#undef isalnum
	#undef isalpha
	#undef isblank
	#undef iscntrl
	#undef isdigit
	#undef isgraph
	#undef islower
	#undef isprint
	#undef ispunct
	#undef isspace
	#undef isupper
	#undef isxdigit
	#undef tolower
	#undef toupper

I suspect/hope that this code is no longer necessary. If it's still necessary, we should find out why, and see if the relevant code can be fixed.