Patch by Ramchandra Apte.

This is a wholesale reorganization and editing of the email documentation to
make the new API the standard one, and the old API the 'legacy' one.  The
default is still the compat32 policy, for backward compatibility.  We will
change that eventually.

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

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

Thanks to Xiang Zhang for the patch.

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.

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.

Patch by Berker Peksag.