add systemtap probe support

[rurban]

See https://sourceware.org/systemtap/wiki/AddingUserSpaceProbingToApps similar to dtrace. primitive support exists via https://github.com/agentzh/perl-systemtap-toolkit also. see also https://docs.python.org/3.6/howto/instrumentation.html

$usesystemtap (sys/sdt.h)

use the same DTRACE macros.