Install common error library in OpenBSD rootfs

[am11]

We need libcom_err.a for NativeAOT shared libraries publish: dotnet/runtime#129580.

[am11]

cc @akoeplinger, @janvorli

[am11]

Sync'd change from dotnet/runtime#129572 as next VMR sync in runtime is reverting it.

[jkotas]

Thanks

[jkotas]

From dotnet/runtime#129580 : "Of course we can't link pure static executable / library with .so reference"

Why do we need to create pure static executables on OpenBSD? Our default story everywhere else is to reference .so for system dependencies.

[am11]

It's mainly for -p:StaticExecutable=true and -p:NativeLib=Static options. This library is in actual VM with standard install, it was missing from rootfs.

[jkotas]

Do we carry the dependencies required by -p:StaticExecutable=true in the rootfs for Linux?

[am11]

Yes, usually they are in the same package. In case of OpenBSD, /crossrootfs/x64/usr/local/heimdal/lib/libkrb5.a is also available, but the difference is that we aren't using their package manager pkg_add to install it but rather wget/curl, which doesn't pull the dependencies. We manually worked out the few dependencies we needed.