CMake error: out-of-tree subdirectory

[mdpiper]

When building coretran, I got the following CMake error during configuration:

CMake Error at CMakeLists.txt:81 (add_subdirectory):
  add_subdirectory not given a binary directory but the given source
  directory
  "/home/conda/feedstock_root/build_artifacts/coretran_1772699619341/work/test"
  is not a subdirectory of
  "/home/conda/feedstock_root/build_artifacts/coretran_1772699619341/work/src".
  When specifying an out-of-tree source a binary directory must be explicitly
  specified.

This halts the build process.

The above happened during a cloud build, but I can reproduce it locally. I tried stepping back the CMake version from 4.* to 3.*, but I got the same flavor of error.

[mdpiper]

I checked on line 81 and the fix was pretty straightforward, just add the target binary directory:

add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/../test ${CMAKE_CURRENT_BINARY_DIR}/test)

With this, everything builds + I can run the tests.

If this is an acceptable solution, I can send a PR.