docgen now lists macro implementation status in the generated rst files.
Adds POSIX definition link property to docgen json API (`posix-definition`) and
changes the `defined` property of docgen json API to `c-definition`. Now that
docgen's api is getting more specified, adds validation checks to docgen to
start codifying the docgen api spec.
To make sure this all looks good, I've added POSIX definition links to signal.h
as a tester.
This script+config should help us generate more consistent documentation wrt.
what we currently support or not.
As an example usage:
$ ./libc/utils/docgen/docgen.py fenv.h
Will spit out an RST formatted table that can be copy+pasted into our docs.
The config is not filled out entirely, but doing so and then updating our docs
would be great beginner bugs for new contributors.
Having python+json generate things like docs, or headers (as imagined in
https://github.com/nickdesaulniers/llvm-project/tree/hdr-gen2) is perhaps
easier to work with than tablegen, and doesn't introduce a dependency on a host
tool that needs to be compiled from llvm sources before building the rest of
the libc. This can probably be merged with whatever we end up doing to replace
libc-hdrgen.
Please use
https://llvm.org/docs/CodingStandards.html#python-version-and-source-code-formatting
for keeping this file formatted.
