This way, one can just run `ctest .` in the build directory and it will only
run Sandboxed API and Sandbox2 tests.
PiperOrigin-RevId: 321342543
Change-Id: I42537e64bfb3127dca00bd92a3f7b35ca64004d9
This change moves away from a classical superbuild which downloads and builds
at build time. Instead, we now follow a "Fetch Content" workflow (available as
FetchContent in CMake 3.11+) and download dependencies at config time.
Rationale: Superbuild projects have the disadvantage that projects cannot
directly access their individual declared targets. This is not a problem with
regular libraries, as those are usually/supposed to be installed. With
Sandboxed API, this is not desirable, as it has dependencies like Abseil and
glog, which are almost always consumed by including their source tree using
add_subdirectory().
Fixes#10 and makes external embedding easier.
PiperOrigin-RevId: 260129870
Change-Id: I70f295f29a6e4fc8c330512c94b01ef10c017166
