Remove unused code detected by PGI compiler

Remove unused code detected by PGI compiler

Minor cleanup to fix warnings issued by the PGI compiler.
- Unused routines have been removed, including ones that
  were never referenced unless specific defines were set
  directly in source files.
- Unreachable breaks have been removed.
- Add a flag to suppress warning that PGI does not
  understand a GCC pragma in the generated parser.cpp

There are still issues with PGI not catching exceptions
in the unit tests, SIMD, and OpenMP.

Change-Id: Ic7900b80e31745aafa031c806f0664734014bbe5