_WIN32 and __CYGWIN__

[Ken Brown]

There's a lot of code in gnulib that contains 'defined _WIN32 && ! 
defined __CYGWIN__'.  The '! defined __CYGWIN__' part is redundant, 
because _WIN32 is never defined on Cygwin.  It used to be defined if the 
GCC option -mno-cygwin was used, but that option has been unsupported 
for many years, starting with GCC 4, I think.

Would the gnulib maintainers be interested in a patch to clean up the 
code by removing '! defined __CYGWIN__' where it is not needed?  Or has 
there been a deliberate decision to support GCC 3 and the -mno-cygwin 
option?  In the latter case, someone would need to audit the code and 
make sure that it is really doing the right thing for GCC 3 with 
-mno-cygwin.  I personally don't think it's worth the trouble, and I 
think the presence of a redundant '! defined __CYGWIN__' is confusing to 
people who read the code.

Ken