Added make with '-B -j 2' on FreeBSD systems so Ruby can build
Added make with '-B -j 2' on FreeBSD systems so Ruby can build

Signed-off-by: Kasper 'kapöw' Grubbe <6840f6fb7841a9d8fda3ac66e134b7c4e97a707c@gmail.com>

kaspergrubbe/ruby-build