CMake Error at BadSHELL_PATH\.cmake:[0-9]+ \(add_custom_target\):
  Error evaluating generator expression:

    \$<SHELL_PATH:>

  "" is not an absolute path\.
Call Stack \(most recent call first\):
  CMakeLists\.txt:[0-9]+ \(include\)
+
CMake Error at BadSHELL_PATH\.cmake:[0-9]+ \(add_custom_target\):
  Error evaluating generator expression:

    \$<SHELL_PATH:Relative/Path>

  "Relative/Path" is not an absolute path\.
Call Stack \(most recent call first\):
  CMakeLists\.txt:[0-9]+ \(include\)
+
CMake Error at BadSHELL_PATH\.cmake:[0-9]+ \(add_custom_target\):
  Error evaluating generator expression:

    \$<SHELL_PATH:;>

  "" is not an absolute path\.
Call Stack \(most recent call first\):
  CMakeLists\.txt:[0-9]+ \(include\)
