8dae49c5e1
We currently use static libraries without any source files to represent header libraries, but Soong actually has cc_library_headers. So to export those in a separate namespace from static libraries, implement them in Make as well. This also adds a nice pretty-warning / pretty-error macro that can be used to print out standard warning messages pointing to the real source file having the problem. Test: Use a header library exported by Soong in a Make module Change-Id: I3486539e247524cb82a20620745fc7be03014e14