This class exists to allow virtual environment creation to be
customized. The constructor parameters determine the builder's
behaviour when called upon to create a virtual environment.
By default, the builder makes the system (global) site-packages dir
*un*available to the created environment.
If invoked using the Python -m option, the default is to use copying
on Windows platforms but symlinks elsewhere. If instantiated some
other way, the default is to *not* use symlinks.
:param system_site_packages: If True, the system (global) site-packages
dir is available to created environments.
:param clear: If True, delete the contents of the environment directory if
it already exists, before environment creation.
:param symlinks: If True, attempt to symlink rather than copy files into
virtual environment.
:param upgrade: If True, upgrade an existing virtual environment.
:param with_pip: If True, ensure pip is installed in the virtual
environment
:param prompt: Alternative terminal prefix for the environment.
:param upgrade_deps: Update the base venv modules to the latest on PyPI
:param scm_ignore_files: Create ignore files for the SCMs specified by the
iterable.
3.7.2: Windows now uses redirector scripts for python[w].exe instead of copying the actual binaries. In 3.7.2 only setup_python() does nothing unless running from a build in the source tree.
3.7.3: Windows copies the redirector scripts as part of setup_python() instead of setup_scripts(). This was not the case in 3.7.2. When using symlinks, the original executables will be linked.
Create a configuration file indicating where the environment's Python was copied from, and whether the system site-packages should be made available in the environment.