ENH: Improve handling of old-style compatibility.

  - Remove CMP_0001 (no slash in target name) and restore
    old CMAKE_BACKWARDS_COMPATIBILITY check for it
  - Replace all checks of CMAKE_BACKWARDS_COMPATIBILITY
    with cmLocalGenerator::NeedBackwardsCompatibility calls
  - Create new CMP_0001 to determine whether or not
    CMAKE_BACKWARDS_COMPATIBILITY is used.
    (old = use, new = ignore)
  - Show CMAKE_BACKWARDS_COMPATIBILITY in cache only when
    CMP_0001 is set to OLD or WARN
  - Update documentation of cmake_policy and cmake_minimum_required
    to indicate their relationship and the 2.4 version boundary
  - When no cmake policy version is set in top level makefile
    implicitly call cmake_policy(VERSION 2.4) which restores
    CMAKE_BACKWARDS_COMPATIBILITY and other 2.4 compatibility
  - Fix tests MakeClean and Preprocess to call
    cmake_policy(VERSION 2.6) because they depend on new policies

1 files changed, 0 insertions, 27 deletions

diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index e9d92b3..356772a 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -1899,19 +1899,6 @@ int cmake::ActualConfigure()
        cmCacheManager::INTERNAL);
     }
 
-  // set the default BACKWARDS compatibility to the current version
-  if(!this->CacheManager->GetCacheValue("CMAKE_BACKWARDS_COMPATIBILITY"))
-    {
-    char ver[256];
-    sprintf(ver,"%i.%i",cmVersion::GetMajorVersion(),
-            cmVersion::GetMinorVersion());
-    this->CacheManager->AddCacheEntry
-      ("CMAKE_BACKWARDS_COMPATIBILITY",ver, 
-       "For backwards compatibility, what version of CMake commands and "
-       "syntax should this version of CMake allow.",
-       cmCacheManager::INTERNAL);
-    }
-
   // no generator specified on the command line
   if(!this->GlobalGenerator)
     {
@@ -2392,20 +2379,6 @@ int cmake::LoadCache()
     {
     return -3;
     }
-
-  // set the default BACKWARDS compatibility to the current version
-  if(!this->CacheManager->GetCacheValue("CMAKE_BACKWARDS_COMPATIBILITY"))
-    {
-    char ver[256];
-    sprintf(ver,"%i.%i",cmVersion::GetMajorVersion(),
-            cmVersion::GetMinorVersion());
-    this->CacheManager->AddCacheEntry
-      ("CMAKE_BACKWARDS_COMPATIBILITY",ver, 
-       "For backwards compatibility, what version of CMake commands and "
-       "syntax should this version of CMake allow.",
-       cmCacheManager::INTERNAL);
-    }
-
   return 0;
 }