Created attachment 381700 [details] emerge --info output and build log I'm quite surprised to find that I can't install stable a2jmidid. I must admit I don't really understand the emerge error, though. As far as I can see, it compiles and then fails to copy the built files.
I get this error as well. However, I can install a2jmidid-9999 from the pro-audio overlay successfully. It references the git repo directly at http://repo.or.cz/w/a2jmidid.git and reading through the commit log, it appears that the issue was fixed by this commit: http://repo.or.cz/w/a2jmidid.git/commit/7f82da7eb2f540a94db23331be98d42a58ddc269
I can confirm this bug.
I get the same error if I have jack2 installed (jack-audio-connection-kit-1.9.10). If I install jack1 (jack-audio-connection-kit-0.124.1), then a2jmidid builds correctly.
Created attachment 402434 [details, diff] Patch to add pthread to the linked libraries Combination of 24e3b8e543256ae8fdfb4b75eb9fd775f07c46e2 and 7f82da7eb2f540a94db23331be98d42a58ddc269.
04 May 2015; Ian Delaney <idella4@gentoo.org> +files/a2jmidid-link.patch, a2jmidid-8-r1.ebuild: add patch to fix linking issue, fixes bug #518382