[grilo-plugins] build: Fail if lua-factory can't be build by default

[Bastien Nocera <hadess src gnome org>]

commit b0e8529fb48093b76a48ed86e3bbd9181ccfe26d
Author: Bastien Nocera <hadess hadess net>
Date:   Thu Sep 24 14:45:24 2015 +0200

    build: Fail if lua-factory can't be build by default
    
    Unless --disable-lua-factory is passed, error out if lua-factory cannot
    be built. We really want distributions to ship lua-factory, as it's how
    the majority of our plugins are implemented.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=754531

 configure.ac |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 4f1c289..dfaa16c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -652,7 +652,7 @@ AC_ARG_ENABLE(lua_factory,
                 [enable Lua plugins (default: auto)]),
         [
                 case "$enableval" in
-                     yes)
+                     yes | auto)
                         if test "x$HAVE_LUA" = "xno"; then
                            AC_MSG_ERROR([lua not found, install it or use --disable-lua-factory])
                         fi