This is NOT an issue with Cygwin, but I have a sneaking suspicion that
some people here may know quite a lot about Cygwin...

I have filed a couple of bugs on ReactOS that are specific to Cygwin.
My knowledge and care is about to run out, if someone happens to care
about running Cygwin 2.5.2 on ReactOS, please take over.  I think it
could be helpful for the ReactOS developers to have the test cases
for these issues condensed into a small C++ program instead of running
shell commands on an actual Cygwin installation.

btrfs volumes inaccessible to Cygwin:
https://jira.reactos.org/browse/CORE-18247 (will retest this later)

Setup doesn't like btrfs volumes either:
https://jira.reactos.org/browse/CORE-18300 (specific to the local
package directory)
It also doesn't /install/ on btrfs volumes even if the local package
directory is on fat32, but it gets complicated and I hope it's just the
same bug with different symptoms.

I also had problems with git(1), it seems mmap(2) is broken. I've
scheduled investigating this until later.


To avoid clutter, I suggest replying on the cygwin-talk list rather
than the cygwin list.

/Oskar