I think all the Android.mk files now are conform the Gingerbread standards. To include it in Gingerbread builds you just need to copy this source to the folder external/opencore in the android source folder. After this you need to set the option BUILD_WITHOUT_PV := true to false in build/core/main.mk, to include the opencore source in the GB build. Currently the build of opencore fails with some errors which we need to fix up one by one to get the build working.