I took a look at the remaining failures to build 7.8 in Xenofarm. There are only 2 of them left:
"localhost"*: Runs out of memory when exporting documentation. Not much of an issue.
"tomoyo": Fails to build Nettle because apparently the libnettle bundle requires m4 to build.
Now m4 isn't a very burdensome requirement, but is it supposed to be there for exorted builds? If so I'll just ask the owner of tomoyo to install it, but usually m4 tasks are taken care of when exporting a source package.
* Awsome name. I must take a look at the node name generation in the client again.