processor, or any that specifies XMM in the CPUID features.  We perform
the equivalent of testing CR4.OSFXSR to verify the operating system
supports the extended FPU save and restore required for SSE.  We also
perform the equivalent of testing CR4.OSXMMEXCPT to verify the operating
system supports unmasked SIMD FPU exceptions.

All changes to the signal handlers and SIMD FPU control word are
restored after the testing is complete.

Tested on the following kernels:
  - 2.2.14-5.0 kernel from RedHat 6.2 that includes their SSE patch
  - 2.4.0-test11 kernel configured for PPro/PII processor (no SSE)
  - 2.4.0-test11 kernel configured for PIII processor (with SSE)