Setuptools includes CFLAGS from when Python was built, which may include
the flag to add debug symbols. This dramatically inflates the size of
our wheels, so this change disables those symbols. We also exclude
source files from the built wheel. _cantera.cpp ends up being ~10 MB
uncompressed, so this is a signifcant savings as well. Overall, the
wheel goes from ~100 MB to ~5 MB.
Add a new option for the Python package to build a source distribution.
It is added as a new interface to simplify copying files. All of the
Cantera plus external library source code is copied into the interface
folder for building.
Actually building the source distribution is handled by the 'build'
package, which becomes a new dependency to build the sdist. 'build'
handles installing all the build-time dependencies in an isolated
environment using specifications in pyproject.toml.
