exewrapper: convert to _tcsxxx functions for Unicode compatability This fixes more than 50 tests on py3 on Windows when enabled, mostly hooks and such that invoked `hg` directly. 187 left to go. I skipped doing the abort printing with Unicode because of apparent issues with MinGW [1]. It may be moot though, as MinGW isn't listed as a supported compiler after 3.4 [2]. [1] https://stackoverflow.com/questions/17700797/printf-wprintf-s-s-ls-char-and-wchar-errors-not-announced-by-a-compil [2] https://wiki.python.org/moin/WindowsCompilers

exewrapper: drop an unused variable