key operations using the GMP library. The default is not to build (or use)
this code unless OPENSSL_USE_GMP is defined (because it will impose header
and linker dependencies that might need specifying too).
- define a HERE variable to indicate where the source tree is (used
very little right now)
- make more use of copying and making attribute changes to {file}.new,
and then move it to {file}
- use 'mv -f' to avoid all those questions to the user when the file
in question doesn't have write attributes for that user.
