Upgraded to 1.4.0. They've changed the build system, so some modifications were needed in the spec and in the patches. Known issues:

- The spec file used to build an "integration" binary, but that doesn't seem to exist anymore.
- ARM64 doesn't work all the time. It looks like the build is ignoring the constraints, because it runs out of memory.
- ppcle64 doesn't work. There's possibly a Go compiler bug, but I haven't had the time to look into it yet (a simple test with gccgo didn't work for me either).