(pinfo_basic::pinfo_basic): Define constructor for new class.
(myself): Initialize from myself_initial.
(set_myself): Set pid and progname from already myself_initial.
* strace.cc (strace::strace): Split apart strace::hello. Send notification to
strace as early as possible.
(strace::hello): Just send clause which describes the current process. This
can now be preceded by early initialization strace output.
* include/sys/strace.h (strace::strace): Declare new constructor.