In the UNIX adapter, remove the UNIX->Win32 environment conversion.
In the UNIX adapter, remove the UNIX->Win32 environment conversion.

It doesn't work because it leaves in the Cygwin-style paths in variables
like PATH and TMP.

(Also, it doesn't build with MSYS because MSYS's old G++ toolchain lacks
std::wstring.)

rprichard/winpty,fracting/winpty,peters/winpty,fracting/winpty,rprichard/winpty,dscho/winpty,fracting/winpty,fracting/winpty,rprichard/winpty,traff/winpty,peters/winpty,rprichard/winpty,peters/winpty,traff/winpty,traff/winpty,peters/winpty,dscho/winpty,traff/winpty,dscho/winpty,dscho/winpty