meson: convert backends directory to Meson

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/meson.build b/meson.build
index ead9420..06755f3 100644
--- a/meson.build
+++ b/meson.build
@@ -321,6 +321,10 @@
 if 'CONFIG_RDMA' in config_host
   rdma = declare_dependency(link_args: config_host['RDMA_LIBS'].split())
 endif
+numa = not_found
+if 'CONFIG_NUMA' in config_host
+  numa = declare_dependency(link_args: config_host['NUMA_LIBS'].split())
+endif
 
 create_config = find_program('scripts/create_config')
 minikconf = find_program('scripts/minikconf.py')
@@ -668,6 +672,7 @@
 common_ss.add(files('cpus-common.c'))
 
 subdir('softmmu')
+subdir('backends')
 subdir('migration')
 subdir('monitor')
 subdir('net')