rbenv: Failing to compile Ruby 2.3.0 on FreeBSD 11.0-CURRENT

I’m trying to install Ruby 2.3.0 on FreeBSD 11.0-CURRENT, and it’s failing in the following way:

Downloading ruby-2.3.0.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/2.3/ruby-2.3.0.tar.bz2
Installing ruby-2.3.0...

BUILD FAILED (FreeBSD 11.0-CURRENT using ruby-build 20160228-5-g522f3ba)

Inspect or clean up the working tree at /tmp/ruby-build.20160311195747.1001
Results logged to /tmp/ruby-build.20160311195747.1001.log

Last 10 log lines:
/tmp/ruby-build.20160311195747.1001/ruby-2.3.0 /tmp/ruby-build.20160311195747.1001 ~
checking for ruby... false
checking build system type... x86_64-unknown-freebsd11.0
checking host system type... x86_64-unknown-freebsd11.0
checking target system type... x86_64-unknown-freebsd11.0
checking for gcc... gcc
checking whether the C compiler works... no
configure: error: in `/tmp/ruby-build.20160311195747.1001/ruby-2.3.0':
configure: error: C compiler cannot create executables
See `config.log' for more details

I’ve uploaded config.log.

Oddly, if I change into /tmp/ruby-build.20160311195747.1001/ruby-2.3.0 and run ./configure, it succeeds.

I’m happy to help with any debugging and / or testing if required.