I was trying to control generation of install rules at a sub-directory level. But it appears that setting CMAKE_SKIP_INSTALL_RULES only works when setting in the scope of the top-level CMake file.

This was being done because some fetched projects try to install items that are not being built nor wanted to be part of the install package.

Changing this value in a sub-directory has no effect.

Is there a way control install rule generation at a directory level?

Never mind; I had made some mistakes in my CMakeLists.txt and looking for the install scripts and targets in the wrong place.

There does seem to be a spurious warning if the top-level CMake file has skip rules enabled and then you disable skip rules in a subdirectory.

CMake Warning in CMakeLists.txt:
  CMAKE_SKIP_INSTALL_RULES was enabled even though installation rules have
  been specified