Potentially work around https://github.com/JuliaLang/julia/issues/9185

This might be a x87-vs-SSE problem, since setting march to i686 for building the deps
but JULIA_CPU_TARGET to pentium4 for JIT code appears to work properly.
Need to verify that this doesn't bring back any of the i686 issues on 32 bit linux though.
Merge pull request #10 from tkelman/patch-1

Potentially work around https://github.com/JuliaLang/julia/issues/9185