Resolve Cross Compile Problems

[p0fi]

If to use pthreads with a cross compiling toolchain the variable THREADS_PTHREAD_ARG has to be set properly. This adds the necessary line to enable cross compiling support with pthreads.

[codecov-io]

Codecov Report

Merging #17 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #17   +/-   ##
=======================================
  Coverage   87.99%   87.99%           
=======================================
  Files           3        3           
  Lines         408      408           
=======================================
  Hits          359      359           
  Misses         49       49

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update b18c857...350bd64. Read the comment docs.

[guangie88]

Thank you for the cross-compilation improvement, noted the change. 😃
For reference, the solution seems to be from: http://www.sdowney.org/2016/11/cross-compiling/