[arch-general] Does makepkg not honor 'provides' of other packages?

Hey, I'm trying to build "luabind" against an alternate "lua" package for c++. Its name is "lua-c++" and it provides "lua". It is installed correctly, yet "luabind" won't build with makepkg because of a missing dependency for "lua" which should have been provided by "lua-c++". What happened here? -- Sven-Hendrik