std_cstring.h: #define away all global functions we will redeclare in namespace ...

std_cstring.h: #define away all global functions we will redeclare in namespace `std'.

	* include/c_std/bin/std_cstring.h: #define away all global
	functions we will redeclare in namespace `std'.
	* libsupc++/eh_alloc.cc (__cxa_allocate_exception): Use
	std::memset, instead of memset.
	* testsuite/19_diagnostics/stdexceptions.cc: Use `std::strcmp',
	not plain `strcmp'.
	* testsuite/21_strings/c_strings.cc: Use `std::strcpy' instead of
	plain `strcpy'.

From-SVN: r42555