While the test was already requiring shell-preserves-root (such as the
internal shell), it wasn't aware that the MSYS 1.0 env command knows how
to expand root by itself!
From cmd.exe try:
env SDKROOT=/ cmd //c echo %SDKROOT%
And get:
C:/MINGW/MSYS/1.0
To be certain we have a good 'env' program the test now requires a shell.
llvm-svn: 215298