Avoid using `uname` with `-o` option

[lemniscati]

• Avoid using uname with -o option, which is not POSIX compliant.
• Resolve the first issue of #69.

[rrthomas]

Thanks for this. My understanding is that uname with no argument is the same as uname -s, which prints the kernel name. Does that indeed print Cygwin on Cygwin? (Sorry if you've already confirmed that it works!)

[lemniscati]

Thank you for consideration.

On my cygwin environment, uname behaves as follows:

$ uname
CYGWIN_NT-10.0-22621
$ uname -s
CYGWIN_NT-10.0-22621
$ uname -o
Cygwin
$

So, uname | grep -q CYGWIN is expected to be successful (exit status: 0) in Cygwin environments.

[rrthomas]

Looks good, thanks!