[CMake] cmake for cygwin

[Yaakov (Cygwin/X)]

On Sun, 2010-10-24 at 10:12 +0200, Hendrik Sattler wrote:
> And: believe it or not, WIN32 and CYGWIN are _not_ in strong contrast. They've 
> got so much in common, starting from the binary file format to all low level 
> stuff that cygwin is never going to change. Live with it.

The "low-level stuff" -- IOW the usage of PE binaries -- is about *all*
Cygwin has in common with Win32.  Everything above that, including the
usage of *NIX/X11 vs Win32/GDI APIs is different, and that represents
the bulk of IF(WIN32) usage.

I have built over 140 source packages with CMake, including KDE, and I
can tell you that the patches required to accommodate not defining WIN32
on Cygwin are far outweighed by what would be necessary to change every
IF(WIN32) to IF(WIN32 AND NOT CYGWIN).  This is why we are insisting on
this change.

Perhaps separate PE/ELF/MACHO conditionals could be used to handle the
very low-level commonalities.  But we must have WIN32 undefined on
Cygwin.


Yaakov
Cygwin Ports