library.static() was being used to determine if a library was static,
shared, or header only, which resulted in header only libraries
behaving like shared libraries, when they should be treated as static
libraries with no sources. Explicitly use library.static(),
library.shared(), and library.header() instead.
Bug: 35228396
Test: builds, manually examine changes to build.ninja and Android.mk
Change-Id: I51729992cc6338deda1396b86f12bc9f73e674d8