In commit ac988cf we made sure to undefine the CONST/VOID macros left
defined by `tcl.h`, but this in turn makes it an issue to include
additional Tcl headers later on (see issue #4808).
One way out is to avoid a global `tcl.h` include. In the process we drop
support for Tcl-enabled MXE builds, which were likely broken anyway due
to the additional Tcl APIs used from `tclapi.cc`.
* `misc/__init__.py`:
* checks if there's a `yosys-abc` in the same directory - if yes, sets the variable `sys._pyosys_abc`
* checks if there's a `share` in the same directory - if yes, sets the variable `sys._pyosys_share_dirname`
* `yosys.cc::init_share_dirname`: check for `sys._pyosys_share_dirname`, use it at the highest priority if Python is enabled
* `yosys.cc::init_abc_executable_name`: check for `sys._pyosys_abc`, use it at at the highest priority if Python is enabled
* `Makefile`: add new target, `share`, to only create the extra targets
* `setup.py`: compile libyosys.so, yosys-abc and share, and copy them all as part of the pyosys build
* `test/arch/ecp5/add_sub.py`: ported `add_sub.ys` to Python to act as a test for the share directory and abc with Python wheels, used in CI
* Created `setup.py`: Python package manifest to build `pyosys` wheels with a custom extension to build and include `libyosys.so` using Make
* `.gitignore`: Added byproducts of the Python wheel build process
* `Makefile`: Added `-undefined dynamic_lookup` to `libyosys.so` so missing symbols can be resolved by importing into a Python interpreter
* `kernel/yosys.cc`: Gated `PyImport_AppendInittab` with `!Py_IsInitialized`; as of Python 3.12, the interpreter is already initialized and `PyImport_AppendInittab` would cause an exception to be raised
* Created `wheels.yml`: CI workflow for building wheels for CPython on:
* Linux (glibc, musl) and Darwin
* x86-64 and arm64
The main speedup is accomplished by avoiding a heap allocation in the common case where the final string length is less than 128. Inlining stringf & vstringf adds an additional improvement.
This makes it possible for yosys commands to return values when invoked
as tcl commands. Right now no commands natively support this, but the
tee command can be used with json output like this:
```tcl
set stat [yosys tee -q -s result.json stat -json -top top]
dict get $stat modules \\top num_cells_by_type \$pmux
```
Or with newline separated lists like this:
```tcl
split [yosys tee -q -s result.string select -list top] "\n"
```
