Set MACOSX_RPATH property default consistently across CMake versions

The MACOSX_RPATH target property was introduced in CMake 2.8.12, but we
currently allow CMake 2.8.8.  Set CMAKE_MACOSX_RPATH to 0 by default
so that we get consistent behavior across all versions of CMake.
Leave a comment explaining when the default should be updated.

Now that we set a MACOSX_RPATH default explicitly, we no longer need to
set CMake Policy CMP0042 as was added in commit 2ad9f474 (Set CMake
Policies CMP0025 and CMP0042 as necessary, 2014-03-11), so remove it.

Change-Id: I8af24a728379176b9e7ab933206eaa956e1c60f2

CMakeLists.txt

@@ -4,13 +4,19 @@ foreach(p
     CMP0020 # CMake 2.8.11
     CMP0022 # CMake 2.8.12
     CMP0025 # CMake 3.0
-    CMP0042 # CMake 3.0
     )
   if(POLICY ${p})
     cmake_policy(SET ${p} NEW)
   endif()
 endforeach()
 
+# Set a consistent MACOSX_RPATH default across all CMake versions.
+# When CMake 2.8.12 is required, change this default to 1.
+# When CMake 3.0.0 is required, remove this block (see CMP0042).
+if(NOT DEFINED CMAKE_MACOSX_RPATH)
+  set(CMAKE_MACOSX_RPATH 0)
+endif()
+
 project(VTK)
 
 # Objective-C++ compile flags.

Examples/Build/vtkLocal/CMakeLists.txt

@@ -2,9 +2,6 @@ cmake_minimum_required(VERSION 2.8.8)
 if(POLICY CMP0025)
   cmake_policy(SET CMP0025 NEW) # CMake 3.0
 endif()
-if(POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # CMake 3.0
-endif()
 project(vtkLocalExample)
 
 # Find and load VTK settings.

Testing/External/CMakeLists.txt

@@ -6,7 +6,6 @@ foreach(p
     CMP0020 # CMake 2.8.11
     CMP0022 # CMake 2.8.12
     CMP0025 # CMake 3.0
-    CMP0042 # CMake 3.0
     )
   if(POLICY ${p})
     cmake_policy(SET ${p} NEW)

ThirdParty/hdf5/vtkhdf5/CMakeLists.txt

@@ -2,9 +2,6 @@ cmake_minimum_required (VERSION 2.8)
 if(POLICY CMP0025)
   cmake_policy(SET CMP0025 NEW) # CMake 3.0
 endif()
-if(POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # CMake 3.0
-endif()
 
 PROJECT (HDF5 C CXX)
 

ThirdParty/verdict/vtkverdict/CMakeLists.txt

@@ -3,9 +3,6 @@ cmake_minimum_required(VERSION 2.8.2)
 if(POLICY CMP0025)
   cmake_policy(SET CMP0025 NEW) # CMake 3.0
 endif()
-if(POLICY CMP0042)
-  cmake_policy(SET CMP0042 NEW) # CMake 3.0
-endif()
 
 project(verdict)
 

Utilities/KWSys/CMakeLists.txt

@@ -15,7 +15,7 @@ SET(KWSYS_USE_FundamentalType 1)
 SET(KWSYS_USE_MD5 1)
 SET(KWSYS_USE_Glob 1)
 set(KWSYS_HEADER_ROOT ${CMAKE_CURRENT_BINARY_DIR})
-SET(KWSYS_PROPERTIES_CXX ${VTK_LIBRARY_PROPERTIES} MACOSX_RPATH 1)
+SET(KWSYS_PROPERTIES_CXX ${VTK_LIBRARY_PROPERTIES})
 SET(KWSYS_INSTALL_EXPORT_NAME ${VTK_INSTALL_EXPORT_NAME})
 
 if(NOT VTK_INSTALL_NO_LIBRARIES)