bldchn, don't use per per-target CPPFLAGS

This safes some build time because now sources which are used by both
targets are not compiled twice.
don't include *.ggo.c but compile them separately
bldchn, add default warnflags also for CC
Merge branch 'bld/no-per-target-CPPFLAGS' into next

* bld/no-per-target-CPPFLAGS:
  bldchn, add default warnflags also for CC
  don't include *.ggo.c but compile them separately
  bldchn, don't use per per-target CPPFLAGS
build fix, add .h2m includes to the dist

The man pages could never be re-built from within distdir. Because
of that pattern rule we never got an error.
bldchn, remove unused include from help2man command line
Merge branch 'bld/fix-dist-man' into next

* bld/fix-dist-man:
  bldchn, remove unused include from help2man command line
  build fix, add .h2m includes to the dist
Merge branch 'next'

* next:
  bldchn, remove unused include from help2man command line
  build fix, add .h2m includes to the dist
  bldchn, add default warnflags also for CC
  don't include *.ggo.c but compile them separately
  bldchn, don't use per per-target CPPFLAGS