Recent update of libgpg-error0 and libassuan0 break curl and Opam (OCaml package manager)

[Michael Soegtrop]

Dear Cygwin Team,

my daily CI of Coq Platform indicates that this update:

libassuan0-2.5.5-1   -> libassuan0-2.5.6-1
libgpg-error0-1.47-1 -> libgpg-error0-1.37-1

breaks Opam, the OCaml package manager, via a failed call to curl as can 
be seen by executing these commands:

$ wget 
https://github.com/fdopen/opam-repository-mingw/releases/download/0.0.0.2/opam64.tar.xz 
-O "opam64.tar.xz"
$ tar -xf "opam64.tar.xz"
$ bash opam64/install.sh --prefix "/usr/$(uname 
-m)-w64-mingw32/sys-root/mingw"
$ opam init --bare --shell-setup --enable-shell-hook --enable-completion 
'default' 'https://opam.ocaml.org' --disable-sandboxing

Replacing the DLLs of libassuan0 and libgpg-error0 with the previous 
versions listed above (just replace the DLLs) fixes this.

I had a look at what happens with Procmon. In the end a call to cygwn 
curl (from a MinGW app) fails. In Procmon I can see that curl 
successfully downloads the file and crashes immediately after closing 
the output file. With the old versions of libassuan0 and libgpg-error0, 
curl succeeds. That this download as such is successful shows that this 
is not a temporary network hickup (I also tested it at least 10 times 
either way).

Usual usages of curl seem to work - I couldn't reduce the failure 
reproduction beyond the above 4 lines and couldn't figure out what is so 
special about the curl call of opam.

This is quite painful for me - I was in the middle of a release of Coq 
Platform (a widely used distribution of the Coq proof assistant), when 
my Windows CI (which does a cygwin based MinGW cross compilation of 
OCaml and Coq) failed. Especially painful is that there is no easy way 
to install older package versions from the command line.

I would appreciate a fast roll back. Otherwise I have to find a way to 
install the older versions without user interaction.

Btw.: I do a daily build test of Coq Platform with a fresh cygwin since 
about 6 years and this is only the fourth failure! I really appreciate 
the stability of cygwin - excellent work!

Best regards,

Michael