I've tried your patch off tree (in my own) however the provided patch libguestfs-syms.patch does not apply correctly for the version of libguestfs-minimal@1.53.6 used:

> applying '/gnu/store/866c9b68vmmyz8vzzk014qdgg13jayfj-libguestfs-syms.patch'...
> patching file lib/Makefile.am
> Hunk #1 FAILED at 160.
> 1 out of 1 hunk FAILED -- saving rejects to file lib/Makefile.am.rej
> patching file lib/Makefile.in
> patch unexpectedly ends in middle of line
> Hunk #1 FAILED at 1109.
> 1 out of 1 hunk FAILED -- saving rejects to file lib/Makefile.in.rej

I've tried newer version of the patch that is a part of libguestfs-1.50.1 nixpkg [1] and it applies correctly (but, I'm not sure what it does or if it is needed at all in Guix..)

Anyway, thank you for your contribution. This pkg is just what I was looking for recently.

Jiri

[1] https://raw.githubusercontent.com/NixOS/nixpkgs/025d82d45cf50400f68f06c5d07458f54926956e/pkgs/development/libraries/libguestfs/default.nix