The build system now uses a :program:`_bootstrap_python` interpreter for
freezing and deepfreezing again. To speed up build process the build tools
:program:`_bootstrap_python` and :program:`_freeze_module` are no longer
build with LTO.
Cross building depends on a build Python interpreter, which must have same
version and bytecode as target host Python.
Instead we use $(PYTHON_FOR_REGEN) .../deepfreeze.py with the
frozen .h file as input, as we did for Windows in bpo-45850.
We also get rid of the code that generates the .h files
when make regen-frozen is run (i.e., .../make_frozen.py),
and the MANIFEST file.
Restore Python 3.8 and 3.9 as Windows host Python again
Co-authored-by: Kumar Aditya <59607654+kumaraditya303@users.noreply.github.com>
Implement changes to build with deep-frozen modules on Windows.
Note that we now require Python 3.10 as the "bootstrap" or "host" Python.
This causes a modest startup speed (around 7%) on Windows.
This gains 10% or more in startup time for `python -c pass` on UNIX-ish systems.
The Makefile.pre.in generating code builds on Eric's work for bpo-45020, but the .c file generator is new.
Windows version TBD.