during "make errors" and thus during "make update".
Fix lots of bugs that util/ck_errf.pl can detect automatically.
Various others of these are still left to fix; that's why
"make update" will complain loudly when run now.
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).