Cygwin WARNING: Couldn't compute FAST_CWD pointer

[pipcet]

I'm seeing this warning when starting the container:

Cygwin WARNING:
  Couldn't compute FAST_CWD pointer.  This typically occurs if you're using
  an older Cygwin version on a newer Windows.  Please update to the latest
  available Cygwin version from https://cygwin.com/.  If the problem persists,
  please see https://cygwin.com/problems.html

My impression (mostly from reading https://bugs.winehq.org/show_bug.cgi?id=40528 , https://cygwin.com/faq.html#faq.using.fixing-find_fast_cwd-warnings , and looking at the code) is this:

1. Cygwin expects a certain internal structure layout that Wine doesn't provide
2. There is fallback code in Cygwin and the actual execution will work okay
3. The warning will still produce unexpected console output
4. Cygwin applications launching other Cygwin applications pass on the information and no additional warnings will be printed
5. Non-Cygwin applications launching Cygwin applications will print an unexpected warning

My conclusion is the underlying problem is most likely harmless; printing the message, however, does cause trouble, because there is unexpected output on stderr and the message itself is not helpful when running on Wine/Linux.

My suggestion would be to disable this warning, either in the image, or in msys2-runtime generally. If necessary, we could make that conditional somehow (registry key?).