own CMakeLists: remove unreachable code

CMakeLists.txt

@@ -69,11 +69,7 @@ if(NOT DEFINED CMAKE_CXX_STANDARD AND NOT CMake_NO_CXX_STANDARD)
   if(CMAKE_CXX_COMPILER_ID STREQUAL SunPro AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.14)
     set(CMAKE_CXX_STANDARD 98)
   else()
-    if(NOT CMAKE_VERSION VERSION_LESS 3.8)
-      include(${CMake_SOURCE_DIR}/Source/Checks/cm_cxx17_check.cmake)
-    else()
-      set(CMake_CXX17_BROKEN 1)
-    endif()
+    include(${CMake_SOURCE_DIR}/Source/Checks/cm_cxx17_check.cmake)
     if(NOT CMake_CXX17_BROKEN)
       set(CMAKE_CXX_STANDARD 17)
     else()
@@ -126,14 +122,12 @@ option(CMake_BUILD_DEVELOPER_REFERENCE
 mark_as_advanced(CMake_BUILD_DEVELOPER_REFERENCE)
 
 # option to build using interprocedural optimizations (IPO/LTO)
-if(NOT CMAKE_VERSION VERSION_LESS 3.12.2)
-  option(CMake_BUILD_LTO "Compile CMake with link-time optimization if supported" OFF)
-  if(CMake_BUILD_LTO)
-    include(CheckIPOSupported)
-    check_ipo_supported(RESULT HAVE_IPO)
-    if(HAVE_IPO)
-      set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
-    endif()
+option(CMake_BUILD_LTO "Compile CMake with link-time optimization if supported" OFF)
+if(CMake_BUILD_LTO)
+  include(CheckIPOSupported)
+  check_ipo_supported(RESULT HAVE_IPO)
+  if(HAVE_IPO)
+    set(CMAKE_INTERPROCEDURAL_OPTIMIZATION TRUE)
   endif()
 endif()
 

CompileFlags.cmake

@@ -87,11 +87,6 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL SunPro AND
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
     if (NOT CMAKE_CXX_STANDARD OR CMAKE_CXX_STANDARD EQUAL 98)
       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++03")
-    elseif(CMAKE_VERSION VERSION_LESS 3.8.20170502)
-      # CMake knows how to add this flag for compilation as C++11,
-      # but has not been taught that SunPro needs it for linking too.
-      # Add it in a place that will be used for both.
-      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
     endif()
   else()
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -library=stlport4")