Usually posix functions have individual doc pages, and each header has its own
list of required macro definitions. Use a simpler key of "in-latest-posix" to
signal that the URL convention can be followed.
Add support for a "removed-in-posix-2008" key which will link to the 2004 docs
for functions like bcmp, bcopy, bzero, index, and rindex from strings.h.
I don't want to add all of these links for pthreads.h, so automating this will
make documenting these go much faster.
[libc][docs] stub out assert, errno, and locale
These were the remaining c89 library headers (besides string.h and
stdlib.h; I
will split strings.rst in a follow up commit).
The macro support detection in docgen doesn't quite work for some of
these
headers. Add the stubs for these headers for now, and fix up docgen
later.
See the "NIST publication":
Link: https://www.open-std.org/jtc1/sc22/wg14/www/projects.html
