Fix pointer aliasing issue for sin and cos by using a union as needed.
* Add rules to compile sincos.c appropriately for each test that we
  want.
* Linux needs -lrt to get clock_gettime. (Needs testing on other
  platforms.)
Rename sin and cos to test_sin and test_cos. This is mostly to defeat
gcc from converting calls to sin and cos to a single call to
sincos. We don't want this optimization for testing.

* sincos.c:
  * New file containing trig functions
* jakes-model.c:
  * Use test_sin and test_cos
  * Remove unneeded stuff.
Merge branch 'tc-39' of github.com:rtoy/crlibm into tc-39