Enable variants of bootstrap modules
Enable variants of bootstrap modules

The primary builder may want to create variants of bootstrap
modules if they need to fit in to the primary builder's dependency
graph.  Enable arbitrary variants of bootstrap modules by only
running the module's actions on the primary variant and then
copying the result to any other variants that exist.

Test: m checkbuild
Change-Id: I24b97771bb11faeacab4079ed8cf69aef59da140

google/blueprint,google/blueprint