The new test 22_locale/collate_wchar_t_members.cc fails on cygwin. The problem seems to be: `wstring' undeclared (first use this function) >From libstdc++-v3/include/bits/stringfwd.h it seems that defining _GLIBCPP_USE_WCHAR_T may fix this. Is this a "good thing"? If so, how do I do it?