81e9bf3445
Don't rely on shell commands. On Ubuntu 20.04, /usr/bin/python no
longer exists, so I'm seeing some failures from somewhere assuming the
path.
The top level CMakeLists also repeats exactly this, which should be
fixed.
Change-Id: I56b26742920f0dc40b363b409892bd41cfa485ef
[ROCm/clr commit: bd4ec781f2]