Assert TriBITS min CMake version in TriBITS itself

Now that the minimum CMake version is 2.8.11, it seems that CMake now allows
to to assert the minimum CMake version in an included file.  Now we can take
the assertion of the minimum CMake version out of the base TriBITS project
CMakeLists.txt file.

tribits/core/package_arch/TribitsProjectImpl.cmake

@@ -58,9 +58,11 @@ IF (${PROJECT_NAME}_VERBOSE_CONFIGURE)
   MESSAGE("CMAKE_MODULE_PATH='${CMAKE_MODULE_PATH}'")
 ENDIF()
 
-INCLUDE(TribitsIncludeDirectories)
-
 INCLUDE(TribitsConstants)
+
+CMAKE_MINIMUM_REQUIRED(VERSION ${TRIBITS_CMAKE_MINIMUM_REQUIRED} FATAL_ERROR)
+
+INCLUDE(TribitsIncludeDirectories)
 INCLUDE(TribitsGlobalMacros)
 INCLUDE(TribitsConfigureCTestCustom)
 

tribits/examples/TribitsExampleProject/CMakeLists.txt

@@ -16,7 +16,7 @@ SET(CMAKE_LEGACY_CYGWIN_WIN32 1 CACHE BOOL "" FORCE)
 # don't process this file.
 #
 
-# Get PROJECT_NAME (must be in file for other parts of system to read)
+# Get PROJECT_NAME (must be in a file for other parts of system to read)
 INCLUDE("${CMAKE_CURRENT_SOURCE_DIR}/ProjectName.cmake")
 
 # CMake requires that you declare the CMake project in the top-level file and
@@ -32,9 +32,6 @@ SET(${PROJECT_NAME}_TRIBITS_DIR
   "TriBITS base directory (default assumes in TriBITS source tree)")
 INCLUDE("${${PROJECT_NAME}_TRIBITS_DIR}/TriBITS.cmake")
 
-# CMake requires this be in the top file and not in an include file :-(
-CMAKE_MINIMUM_REQUIRED(VERSION ${TRIBITS_CMAKE_MINIMUM_REQUIRED})
-
 # Set default location for header-only TPL to make easy to configure out of
 # the TriBITS source tree.
 SET(HeaderOnlyTpl_INCLUDE_DIRS

tribits/examples/TribitsHelloWorld/CMakeLists.txt

@@ -12,11 +12,10 @@ INCLUDE(${CMAKE_CURRENT_SOURCE_DIR}/ProjectName.cmake)
 PROJECT(${PROJECT_NAME} NONE)
 
 SET(${PROJECT_NAME}_TRIBITS_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../..
-  CACHE PATH "Path to TriBITS.")
-INCLUDE("${${PROJECT_NAME}_TRIBITS_DIR}/TriBITS.cmake")
+  CACHE PATH "TriBITS base directory (default assumes in TriBITS source tree).")
 
-# CMake requires this be in the top file and not in an include file :-(
-CMAKE_MINIMUM_REQUIRED(VERSION ${TRIBITS_CMAKE_MINIMUM_REQUIRED})
+# Include the TriBITS system
+INCLUDE("${${PROJECT_NAME}_TRIBITS_DIR}/TriBITS.cmake")
 
 # Disable MPI and Fortran
 SET(TPL_ENABLE_MPI OFF CACHE BOOL "" FORCE)