[CMake] Dependency on imported target with ninja-generator

[Patrick Boettcher]

Hi list,

I'm finding myself in the following situation.

- Project A generates libmain.a and export(TARGETS ... NAMESPACE ns) it
  to a file. The target is called ns::main

- Project B includes this file and has some executables link with
  libmain.a (via target_link_libraries(exe ns::main).

- Project B's CMakeLists.txt contains a add_custom_target(build ...)
  which runs cmake --build in project A's build-dir.

- the target build is a add_dependency() of ns::main.

Building it with gnu-make works like a charm - make is entering project
A's build-dir before linking.

Building it with ninja fails with not finding libmain.a - which is
normal it has not yet been built. Ninja seems to evaluate the complete
dependency-tree of files before doing anything.

Is there a way to fix this?

Thanks.

best regards,
--
Patrick.