tests/qtest: libqos: Do not build virtio-9p unconditionally

At present the virtio-9p related codes are built into libqos
unconditionally. Change to build them conditionally by testing
the 'virtfs' config option.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20221028045736.679903-9-bin.meng@windriver.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

tests/qtest/libqos/meson.build

@@ -33,8 +33,6 @@ libqos_srcs = files(
         'sdhci.c',
         'tpci200.c',
         'virtio.c',
-        'virtio-9p.c',
-        'virtio-9p-client.c',
         'virtio-balloon.c',
         'virtio-blk.c',
         'vhost-user-blk.c',
@@ -62,6 +60,10 @@ libqos_srcs = files(
         'x86_64_pc-machine.c',
 )
 
+if have_virtfs
+  libqos_srcs += files('virtio-9p.c', 'virtio-9p-client.c')
+endif
+
 libqos = static_library('qos', libqos_srcs + genh,
                         name_suffix: 'fa',
                         build_by_default: false)