cmake and CONFIGURE_DIR

[nia <nia%NetBSD.org@localhost>]

How does the new cmake/build.mk system work with non-root
configure directories?

I have a package with CMakeLists.txt in the "gtk" subdirectory.

Before, you'd set CONFIGURE_DIRS and BUILD_DIRS and then
it'd run the cmake script in that directory.

The new cmake system seems to have CONFIGURE_DIR, but setting
it seems to do nothing and the package complains about missing
CMakeLists.txt.