pid/gid mess improved
Fix other.test_valid_abspath broken by previous feature to never warn when an absolute path points inside the emscripten tree.
Make is_valid_abspath use path_from_root() to be more precise about what Emscripten root directory is.
Add test that rand() produces both even and odd numbers (fails). See #2341.
Migrate to musl v1.0.3 prng functions. Fixes #2341. Bump version to 1.23.1 to have cached libc rebuilt with prng routines.
Improve test_rand to test all produced bits, not just the lowest one.
Merge pull request #2719 from juj/musl_rand

Musl rand
relax other.test_outline limits some more
make stack align to 16 bytes in fastcomp, as the fastcomp backend does; #2721
Fix SDL_UpperBlit
Source size was used in destination size when drawing image
test for 32-byte alignment; #2721
remove no longer needed rand_seed hack
Merge pull request #2722 from FishingCactus/fix-sdl_upper_blit

Fix SDL_UpperBlit
fix regression on non-fastcomp stack alignment
Merge pull request #2718 from hamishwillee/incoming

Restructure Files section.
portability_guidelines.rst updates
Merge pull request #2660 from socketpair/pid_gid_mess

pid/gid mess improved
minor clarifications to file system behaviour
minor editorial updates. Add TODO note to debugging topic