This removes <dep/dep.h> by renaming it to <pproto/lib.h>, since those
functions are library ones, though pp_ prefixed.

<pproto/pproto.h> includes <pproto/lib.h>, since they are always needed,
and C files are fixed by not including <dep/dep.h>. Sometimes I included
<pproto/diag.h> to fix some compile warnings for implicit declaration of
pp_printf.
Signed-off-by: Alessandro Rubini <rubini@gnudd.com>
Acked-by: Aurelio Colosimo <aurelio@aureliocolosimo.it>