- Restore -nostdinc that got lost in rev.1.105; we don't   want host headers during `buildworld'.
- Restore -nostdinc that got lost in rev.1.105; we don't
  want host headers during `buildworld'.

- During `buildworld', install headers in a "copy" mode
  until we decide what to do with the (currently broken)
  SHARED=symlinks.

- Temporarily run `buildworld' with -DNO_WERROR, which
  effectively disabled the -Werror bit of recently added
  WARNS=X feature.  This is required because adding the
  -nostdinc bit back revealed bugs in some header files
  that were hiding after not using -nostdinc.
  It is unclear currently how exactly (and why) -nostdinc
  affects gcc(1) warnings.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase