The signal module was using old-style module initialization with
potential NULL dereferencing.

CID 1295026

In the case of an escape character, c is never read. tok_next() is
used to advance the pointer.

CID 1225097

                   documentation consistent with the code.

Issue #21201: Improves readability of multiprocessing error message from server to client for certain exceptions

Patch by Claude Paroz.

Initial patch contributed by Denver Coneybeare.

between runs given the same Grammar.txt input regardless of the hash
randomization setting.

required for PGO linking - to be a configure time error rather than
make time when --with-optimizations is enabled.  Also improve our
ability to find the llvm-profdata tool on MacOS and some Linuxes.

Original patch by Martin Panter, new policy fixes by me.

modules.

Initial patch by Alex LordThorsen.