Avoid looking for local ssh binary
When cross-compiling gvfs (think of openembedded or buildroot) using the full path of local binaries doesn't make sense.
For example the gvfsd-sftp backend breaks because it uses the ssh path of the host machine where build happened:
https://gitlab.gnome.org/GNOME/gvfs/-/blob/1.44.1/meson.build#L456
https://gitlab.gnome.org/GNOME/gvfs/-/blob/1.44.1/daemon/meson.build#L259
https://gitlab.gnome.org/GNOME/gvfs/-/blob/1.44.1/daemon/gvfsbackendsftp.c#L244
It should at least be possible to override the SSH_PROGRAM value when calling meson.
Edited by Diego Rondini