* SunOS linker doesn't support --gc-sections
 * Add portable_endian.h with __sun version of htole64 and le64toh
   * Replace portable endian code in shake.c with inclusion of portable_endian.h
   * Replace portable endian code in word.h with inclusion of portable_endian.h
 * Add explicit extern reference to word.h for posix_memalign when __sun defined
 * Replace references to u_int*_t with uint*_t
 * rdtsc call in shake.c was only working on 32-bit i386
 * rdtsc call in bench_decaf.cxx was inaccurate on 64-bit x86_64 when clang absent
 * Fix two signed/unsigned comparison errors in test_decaf.cxx