The configure script no longer recognizes "CONFIG_UTF_8=yes" lines
in custom features.conf files. They will have to be changed to
"CONFIG_UTF8=yes". This incompatibility was deemed acceptable
because no released version of ELinks supports CONFIG_UTF_8.
The --enable-utf-8 option was not renamed.
Finally, we are able to identify the builds more accurately. Now we check
if commit-id (cogito tool) is available and pass the output to vernum.c
compilation which then exports it as a build_id string.
The first line of --version is now a bit long, we should probably move the
build date to a second indented line or something.
