System: Add SwapByteOrder and update Support/MathExtras.h to use it.

llvm-svn: 116234
4 files changed
tree: 7d2f08eeda9ea20e63a9530bc75e490aecb7149d
  1. clang/
  2. compiler-rt/
  3. debuginfo-tests/
  4. libcxx/
  5. lldb/
  6. llvm/