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.
Sahnvour
Andrew Kelley