Make conf.bins work for cross compiled deps as well as the host.
Test ruby library should depend on host's mrbc, not its own mrbc
Merge pull request #717 from xxuejie/master

Host's mrbc file should be used when cross-compiling mrbtest.c
Merge pull request #716 from carsonmcdonald/crossdepfix

Make conf.bins work for cross compiled deps as well as the host.