contrib/vhost-user-blk: convert to Meson

The GLib pkg-config information is extracted from config-host.mak and
used to link vhost-user-blk.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

contrib/vhost-user-blk/Makefile.objs

@@ -1 +0,0 @@
-vhost-user-blk-obj-y = vhost-user-blk.o

contrib/vhost-user-blk/meson.build

@@ -0,0 +1,6 @@
+# FIXME: broken on 32-bit architectures
+executable('vhost-user-blk', files('vhost-user-blk.c'),
+           link_with: libvhost_user,
+           dependencies: qemuutil,
+           build_by_default: false,
+           install: false)