bug#36811: Guix fails to build with libgc 8.0.4

Just for the record: Ludo added libgc-8 in 69961ac3b9db2dbb99abb5c45ff6be3a9c01b5de on master. It's not yet used, so we need to replace libgc-7.6 with it and see how it goes...

bug#39118: Segfault while building on 64-bit Cygwin

On Fri, Jan 31, 2020 at 09:23:19AM -0500, John Cowan wrote: > Aaaand... Cygwin doesn't do core dumps. Under the skin it's WIndows, after > all. This is what I get when I specify ulimit -c unlimited and rebuild: > [...] Please see my previous mail on how to get a real core dump on cygwin https://d