Even though we aren't doing any linking for static libraries, the
default libraries (libc, libm, libdl) are now exporting headers, so we
should be using those for both static and shared libraries (especially
when re-using objects between the two). Without this we've been in a
state where a cc_library will compile differently than a
cc_library_shared, as we'd re-use the compilation units from the static
variant in the shared library.
This does require marking many of libc's dependencies as not using libc
with system_shared_libs, otherwise we run into dependency loops.
Test: treehugger
Change-Id: Ie42edc5184f315f998db953594e425214b810e0e
3a26eefdbe