mitchellh/vagrant-installers — pull request #29 by tendervittles (2013-11-10 22:43:16+00:00)
Title: CFLAGS and LDFLAGS had bad values.

The -I flag in gcc is a preprocessor flag. Replace CFLAGS with CPPFLAGS. It should not take link options.
The LDFLAGS should not take preprocessor options.

I wrote up a bug at https://github.com/mitchellh/vagrant/issues/2427 before I knew how the project was divided.