v0.0.53

• tools/check_nodiscard.py, new (#124): every internal function returning bool carries the library's <PP>_NODISCARD, every one in a src/ header and every static one in a source file, parts in tools/source-dirs.txt included. It reads the library's macro from base.h, takes standard attributes and the two-line bool / name( shape clang-format writes, and fails on a bool declaration in any other shape. Run it with --self-test and without in check.sh's rules step.
• maul-conventions.md states the rule and lists the check.
• src/inflate.c, src/elementary.c and src/elementary_float.c (renamed files) mark their static bool functions; the two elementary files include @LIB@/base.h.

Each library takes these by syncing to this tag, wires the check into check.sh, and marks its own bool functions in the same pull request, with (void) where a drop is deliberate.