sync perl mods

add script to do the above

reduced required subdir-link-time dependencies to speed things up and greatly reduce the size of build files

fix issue where the linker line in meson was too long : now we build each src subdir into its own static library then link all the static libraries. This should not hit the command-line length limit.

add some more meson helper scripts

clean more scripts with shellcheck

put in a compiled test for CPU frequency (when available)

cleaned up some of the meson build stuff so we require fewer bash scripts and use more native compilation instead

meson now checks for setitimer and sets __HAVE_SETITIMER__ if found

reset_timeout no longer requires LINUX, rather it requires __HAVE_SETITIMER__

update reset_timeout to not call setitimer if TIMEOUT_SECONDS is zero : this isn't required because no timeout will ever have been set

now builds a static library which can be then be used
to build the executable and shared library. This reduces the
dependency list and speeds up builds because we no longer
have to build the object files twice (or worse!).

added a meson/pgo.sh script to do profile-guided optimization
automatically

build for distribution of 2.1.4