meson now checks for setitimer and sets __HAVE_SETITIMER__ if found

reset_timeout no longer requires LINUX, rather it requires __HAVE_SETITIMER__

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

more updates to meson: new option binary_c_install_legacy to install binary_c and libbinary_c in the src tree (the legacy location)

sync latest perl mods
meson now detects the version dynamically
update meson sourcefile searcher scripts
fix PCH dependencies in meson build

backwards compatibility