We revert commit "Create CMake Policy CMP0015 to fix set(CACHE)" because
the NEW behavior of the policy breaks a valid use case:
# CMakeLists.txt
option(BUILD_SHARED_LIBS "..." ON)
add_library(mylib ...)
set(BUILD_SHARED_LIBS OFF) # we want only mylib to be shared
add_subdirectory(ThirdParty)
# ThirdParty/CMakeLists.txt
option(BUILD_SHARED_LIBS "..." ON)
# uh, oh, with NEW behavior this dir uses shared libs!!!
We'll re-introduce the policy later with a different change in behavior
to resolve the motivating case, which was more subtle but less common.
See issue #9008.
This converts the CMake license to a pure 3-clause OSI-approved BSD
License. We drop the previous license clause requiring modified
versions to be plainly marked. We also update the CMake copyright to
cover the full development time range.
The set(CACHE) and option() commands should always expose the cache
value. Previously we failed to expose the value when it was already set
if a local variable definition hid it. When set to NEW, this policy
tells the commands to always remove the local variable definition to
expose the cache value. See issue #9008.
This introduces the unset() command to make it easy to unset CMake
variables, environment variables, and CMake cache variables. Previously
it was not even possible to unset ENV or CACHE variables (as in
completely remove them). Changes based on patch from Philip Lowman.
See issue #7507.
