linkage that is not in any other header in misc.h. Remove some
redundant declarations elsewhere.
(prompt, doredir, dopipe, doexecute, output, screen, parsedelay):
Static linkage.
thread entrypoints:
(lwpSelect, shutdown_sequence): Parameters didn't match thread entry
point prototype.
(lwpEntryPoint): Arguments didn't match thread entry point prototype.
Change linkage of functions without prototype declaration to static
where possible.
Remove some superflous declarations, replace others by suitable
includes.
