What's to understand?  Some compilers, particularly MinGW and Open Watcom, already define a PATH_MAX macro on Windows, and it's not necessarily the same as Python's redefinition of it, possibly causing a compiler error.  That's all.

Given the time frame that this bug has existed (9 months!?!) and its trivial fix, which would involve adding an  "#ifndef PATH_MAX" right before its declaration, I think "won't fix" is an appropriate resolution.

Leave it open or don't, it makes little difference to me as I'm no longer interested.