Remove CMake Policy CMP0015 until it is revised

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.

1 files changed, 0 insertions, 1 deletions

diff --git a/Source/cmPolicies.h b/Source/cmPolicies.h
index be3b44a..cf808bd 100644
--- a/Source/cmPolicies.h
+++ b/Source/cmPolicies.h
@@ -50,7 +50,6 @@ public:
     CMP0012, // Strong handling of boolean constants
     CMP0013, // Duplicate binary directories not allowed
     CMP0014, // Input directories must have CMakeLists.txt
-    CMP0015, // set(CACHE) and option() make CACHE value visible
 
     // Always the last entry.  Useful mostly to avoid adding a comma
     // the last policy when adding a new one.