#4 combo box fix for cygwin

[John Williams]

On cygwin, the popup part of a combo box always
appears in the top right corner of the screen. This
is because os.name == "posix" in cygwin Python. To
fix this problem, change PmwBase.py line 234 from
this:

if os.name == 'nt':

to this:

if os.name == 'nt' or sys.platform == 'cygwin':

[Greg McFarlane]

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The value of sys.platform in the version of cygwin
I have access to is "cygwin_nt-4.01".

Would this be a better patch?:

if os.name == 'nt' or \ os.name == 'posix' and \ string.find(sys.platform, 'cygwin') == 0:

[John Williams]

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This looks good to me. As a matter of style I'd prefer
sys.platform.startswith('cygwin'), but then again this
method only seems to have appeared in Python 2.1; I'm not
sure how important it is to be backward compatible.