libcxx Is there any difference between noexcept and _NOEXCEPT ?

I view this page, found the patch mixed up noexcept and _NOEXCEPT, is that reasonable?
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/bitset?sortdir=down&r1=119571&r2=132216&sortby=rev&diff_format=h

Hello,

I view this page, found the patch mixed up noexcept and _NOEXCEPT, is that reasonable?
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/bitset?sortdir=down&r1=119571&r2=132216&sortby=rev&diff_format=h

The lines using "noexcept" belong to the (commented out) synopsis of the header. "_NOEXCEPT" is
used in the real source, so libc++ can be used with compilers that don't support "noexcept" (yet).

HTH,
Jonathan