meson: pass rustc_args when building all crates

rustc_args is needed to smooth the difference in warnings between the various
versions of rustc.  Always include those arguments.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
3 files changed