Add the constexpr version of max which is only available in std since c++14.
Besides being a logical addition next to the already implemented constexpr version of min, there are actually other files, even in Swift/Basic itself, which re-implement this functionality, such as PrefixMap.h. Once this is implemented here, the functionality can be re-used in those other locations, instead of re-implemented each time.
- Added missing ifdef guard in PointerIntEnum header
- Consistent naming convention for ifdef guards
- Consistent 'end namespace swift'
- Consistent single EOL at end of header files
<rdar://problem/19104060>
LLVM's PointerIntPair always picks the highest bits of the available low
order free bits but NumLowBitsAvailable is the number of *lowest* bits
available from the LSB. This could cause problems with overwriting when
putting a FlaggedPointer inside a PointerIntPair. Just don't allow it.
Add a static assert to make sure there are enough bits to support the
number of nested FlaggedPointers.
Add a helper constexpr min function which isn't available until C++14.
Swift SVN r23597
