fix protoc 3.4.1 usage

protoc 3.4.1 reports a libprotoc version of 3.4.0, so we need to check the version matching without the last number. This is done both in contribs and in the configure script. The configure script uses a modified version of !2585 (closed). For now we keep allowing HOST-protoc.

The docker images are updated to include protoc 3.4.1 so it's not rebuilt each time. Only the gcc win64 image is kept for now as it fails to build gcrypt due to a gcc bug.