I've got 1.15.0-beta.3 building on Fedora rawhide -- main build for most arches and s390x is separate. It takes a while for some to complete, especially armv7hl, but the faster ones ought to be done by now. Instead I'm seeing:
test [run-pass] run-pass/env-funky-keys.rs has been running for over 60 seconds
That's the current state on x86_64, ppc64, and s390x at least. Looking at this test, it could get into an infinite exec loop if the arg count didn't work for some reason. Rawhide has a prerelease glibc, so it could be something weird there too. I'll try to reproduce this locally and file a bug...
edit: I'm also aware that beta.3 is not current with the beta branch, but nothing new there looks relevant.
edit2: I confirmed this in a local rawhide root, and copying that exact
env-funky-keys binary to Fedora 25 runs fine. I'm calling this one a glibc issue for the moment... rhbz 1414589