* introduce std.json.WriteStream API for writing json
data to a stream
* add WIP tools/merge_anal_dumps.zig for merging multiple semantic
analysis dumps into one. See #3028
* add std.json.Array, improves generated docs
* add test for `std.process.argsAlloc`, improves test coverage and
generated docs
This is the beginning of supporting minimum GLIBC version as part of the
target. See #2509 for the motivation.
The dummy libc zig files are removed. A future commit will build them
on-the-fly, using the generated text files generated by the new tool,
which are checked into source control and distributed along with zig.
These generated text files are, together, 142KB (20KB gzipped).
Compare that to a naive bundling of the .abilist files, which would be
2.2MiB (375KB gzipped).
This is based on glibc 2.29.
