build: add --with-python option
This adds a new --with-python option to allow configuration of the python binary
for building. If not specified, $PATH will be searched for common python binary
names (python, python2, python3). If specified, and the path is not executable,
it will attempt to search $PATH.
Signed-off-by: Saleem Abdulrasool <compnerd@compnerd.org>
Reviewed-by: Eric Christopher <echristo@gmail.com>, Daniel Dunbar <daniel@zuster.org>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173890
91177308-0d34-0410-b5e6-
96231b3b80d8