When using alpine as host, things start to fail. Lets pull in the
upstream alpine patches to make things work. This should not affect
other hosts.
Note, that Alpine has the '_GNU_SOURCE' define in the APKBUILD file, but
here we add this flag to the needed fix flags patch, which does similar
things too.
Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>