lua: handles BR2_PREFER_STATIC_LIB

fix compilation with Blackfin FLAT

see http://autobuild.buildroot.net/results/b41/b4146bf821d59f694546f6e3a341394cc8fa43ce/

Signed-off-by: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
diff --git a/package/Config.in b/package/Config.in
index fca61d6..46c4ba4 100644
--- a/package/Config.in
+++ b/package/Config.in
@@ -362,7 +362,8 @@
 source "package/lua/Config.in"
 source "package/luainterpreter/Config.in"
 source "package/luajit/Config.in"
-if BR2_PACKAGE_HAS_LUA_INTERPRETER
+if BR2_PACKAGE_HAS_LUA_INTERPRETER && !BR2_PREFER_STATIC_LIB
+# lua modules are dynamically loaded, so not available on static builds
 menu "Lua libraries/modules"
 source "package/cgilua/Config.in"
 source "package/copas/Config.in"