As noted on IRC, the filenames of the gitian build results do not contain the 4th digit of the version number if it has one, e.g. 0.17.0.1 produces files with the number 0.17.0. Furthermore, when RC's are built, the resulting filenames are of the release version and do not include rc in them. This occurs because configure.ac is written to create version numbers of the form major.minor.rev instead of major.minor.rev.build and without any rc version as it does not handle rc numbers.
This PR changes configure.ac to include the build number if it is greater than 0. It will also include the rc number if it is greater than 0. So the filenames of the gitian builds will now contain the full version number.
This behavior can be tested by setting _CLIENT_VERSION_BUILD and _CLIENT_VERSION_RC to non-zero values and then doing make dist. A tar file should be created with the correct versioning.