virtfs: convert to meson

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

configure

@@ -315,7 +315,7 @@ netmap="no"
 sdl="auto"
 sdl_image="auto"
 virtiofsd="auto"
-virtfs="$default_feature"
+virtfs="auto"
 libudev="auto"
 mpath="auto"
 vnc="enabled"
@@ -1004,9 +1004,9 @@ for opt do
   ;;
   --enable-qom-cast-debug) qom_cast_debug="yes"
   ;;
-  --disable-virtfs) virtfs="no"
+  --disable-virtfs) virtfs="disabled"
   ;;
-  --enable-virtfs) virtfs="yes"
+  --enable-virtfs) virtfs="enabled"
   ;;
   --disable-libudev) libudev="disabled"
   ;;
@@ -5476,24 +5476,6 @@ if [ "$eventfd" = "yes" ]; then
   ivshmem=yes
 fi
 
-if test "$softmmu" = yes ; then
-  if test "$linux" = yes; then
-    if test "$virtfs" != no && test "$cap_ng" = yes && test "$attr" = yes ; then
-      virtfs=yes
-    else
-      if test "$virtfs" = yes; then
-        error_exit "VirtFS requires libcap-ng devel and libattr devel"
-      fi
-      virtfs=no
-    fi
-  else
-    if test "$virtfs" = yes; then
-      error_exit "VirtFS is supported only on Linux"
-    fi
-    virtfs=no
-  fi
-fi
-
 # Probe for guest agent support/options
 
 if [ "$guest_agent" != "no" ]; then
@@ -5950,9 +5932,6 @@ fi
 if test "$libattr" = "yes" ; then
   echo "CONFIG_LIBATTR=y" >> $config_host_mak
 fi
-if test "$virtfs" = "yes" ; then
-  echo "CONFIG_VIRTFS=y" >> $config_host_mak
-fi
 if test "$vhost_scsi" = "yes" ; then
   echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
 fi
@@ -6624,7 +6603,7 @@ NINJA=$ninja $meson setup \
         -Dcurl=$curl -Dglusterfs=$glusterfs -Dbzip2=$bzip2 -Dlibiscsi=$libiscsi \
         -Dlibnfs=$libnfs -Diconv=$iconv -Dcurses=$curses -Dlibudev=$libudev\
         -Drbd=$rbd -Dlzo=$lzo -Dsnappy=$snappy -Dlzfse=$lzfse \
-        -Dzstd=$zstd -Dseccomp=$seccomp \
+        -Dzstd=$zstd -Dseccomp=$seccomp -Dvirtfs=$virtfs \
         -Ddocs=$docs -Dsphinx_build=$sphinx_build -Dinstall_blobs=$blobs \
         -Dvhost_user_blk_server=$vhost_user_blk_server \
         -Dfuse=$fuse -Dfuse_lseek=$fuse_lseek \