CMake Error at BadEmpty\.cmake:1 \(add_custom_target\):
  Error evaluating generator expression:

    \$<>

  Expression did not evaluate to a known generator expression
Call Stack \(most recent call first\):
  CMakeLists\.txt:[0-9]+ \(include\)
+
CMake Error at BadEmpty\.cmake:1 \(add_custom_target\):
  Error evaluating generator expression:

    \$<:foo>

  Expression did not evaluate to a known generator expression
Call Stack \(most recent call first\):
  CMakeLists\.txt:[0-9]+ \(include\)
