ENH: Change cmake support ranges

Be in sync with Slicer and ITK cmake minimums.

Author: hjmjohnson

CMakeLists.txt

@@ -1,5 +1,5 @@
-cmake_minimum_required(VERSION 3.16.3...3.20.3)
-cmake_policy(VERSION 3.16.3...3.20.3)
+cmake_minimum_required(VERSION 3.20.6...4.1.2 FATAL_ERROR)
+cmake_policy(VERSION 3.20.6...4.1.2)
 
 #-----------------------------------------------------------------------------
 # Enable C++17
@@ -15,7 +15,7 @@ endif()
 if(NOT CMAKE_CXX_EXTENSIONS)
   set(CMAKE_CXX_EXTENSIONS OFF)
 endif()
-set(VALID_CXX_STANDARDS "17" "20" "23")
+set(VALID_CXX_STANDARDS "17" "20" "23" "26")
 if(NOT CMAKE_CXX_STANDARD IN_LIST VALID_CXX_STANDARDS )
    MESSAGE(FATAL_ERROR "CMAKE_CXX_STANDARD:STRING=${CMAKE_CXX_STANDARD} not in know standards list\n ${VALID_CXX_STANDARDS}  for BRAINSTools version 5 and greater.")
 endif()

SuperBuild/External_zlib.cmake

@@ -50,7 +50,7 @@ if(NOT DEFINED ZLIB_ROOT AND NOT ${CMAKE_PROJECT_NAME}_USE_SYSTEM_${proj})
     INSTALL_DIR ${EP_INSTALL_DIR}
     CMAKE_CACHE_ARGS
       ## CXX should not be needed, but it a cmake default test
-      -DCMAKE_POLICY_VERSION_MINIMUM=3.20.6
+      -DCMAKE_POLICY_VERSION_MINIMUM:STRING=3.20
       ${EXTERNAL_PROJECT_DEFAULTS}
       -DCMAKE_CXX_COMPILER:FILEPATH=${CMAKE_CXX_COMPILER}
       -DCMAKE_C_COMPILER:FILEPATH=${CMAKE_C_COMPILER}