Help: Add that CMAKE_CACHEFILE_DIR might not be defined
CMake only sets CMAKE_CACHEFILE_DIR
when writing CMakeCache.txt
,
so the variable will usually be undefined when CMakeLists.txt
runs.
Revise its documentation to clarify that CMAKE_BINARY_DIR
should
be used instead.
I ran into this problem myself, and using CMAKE_BINARY_DIR
works even before CMakeLists.txt
has been written.
Backport: release