blockdev: Modularize nfs block driver

Modularizes the nfs block driver so that it gets dynamically loaded.

Signed-off-by: Colin Lord <clord@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1471008424-16465-5-git-send-email-clord@redhat.com
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/configure b/configure
index 7d083bd..2efc338 100755
--- a/configure
+++ b/configure
@@ -4578,7 +4578,6 @@
   if $pkg_config --atleast-version=1.9.3 libnfs; then
     libnfs="yes"
     libnfs_libs=$($pkg_config --libs libnfs)
-    LIBS="$LIBS $libnfs_libs"
   else
     if test "$libnfs" = "yes" ; then
       feature_not_found "libnfs" "Install libnfs devel >= 1.9.3"
@@ -5351,7 +5350,8 @@
 fi
 
 if test "$libnfs" = "yes" ; then
-  echo "CONFIG_LIBNFS=y" >> $config_host_mak
+  echo "CONFIG_LIBNFS=m" >> $config_host_mak
+  echo "LIBNFS_LIBS=$libnfs_libs" >> $config_host_mak
 fi
 
 if test "$seccomp" = "yes"; then