return correct status from configure & make

previously configure would always return success on exit because
tee would always return success, so now we echo the exit status
into the log and check it before returning.

make did not use a log file at all (for this reason presumably)
so now we do the same here as with configure.

separately, the DESTDIR check would fail if directories were
found by 'grep DESTDIR *' with a return status of 2. now a one
liner will only grep files for DESTDIR, and return immediately if
one grep succeeds.
add the script's original directory to the PATH

resolve other scripts that exist in the same directory by resolving
the original directory and adding it to the PATH. consider the
security implications of this when you set up your own PATH.
add 'doc/docs' to copy and chown root the docs dir