Add code at the end of `_sysconfigdata.py` that modifys `build_time_vars` at
module load time with python syntax.
Remove all the sed replaces from PKGBUILD because its hard to review and prone to breakage
Finally a test is added to detect syntax errors next time early on
Fixes https://github.com/msys2/MINGW-packages/issues/5048
* Initial python-3.7 port
* python3: Add setup.config.in to remove before patching
* python3: Implement setenv for mingw. Fix building with NT threads. Build
with unicode
* Fix typos
* Fix linking core modules
* Mingw build have exec_prefix
* Remove deprecated patch
* Fix building python and modules. Failing to build readline module and
install not working yet
* More getpath changes and more aggressive path separator conversion
* Fix readline module compilation and linking errors
* python3: By default building with posix threads, NT threads are broken.
Some patches optimization. First buildable commit
* Py_DecodeLocale handle char, not wchar
* Fix building multiprocessing module with posix threads
