Update SunPro flags used for CMake itself to support C++11

CMakeLists.txt

@@ -55,11 +55,15 @@ if(NOT DEFINED CMAKE_C_STANDARD AND NOT CMake_NO_C_STANDARD)
   endif()
 endif()
 if(NOT DEFINED CMAKE_CXX_STANDARD AND NOT CMake_NO_CXX_STANDARD)
-  include(${CMake_SOURCE_DIR}/Source/Checks/cm_cxx14_cstdio.cmake)
-  if(NOT CMake_CXX14_CSTDIO_BROKEN)
-    set(CMAKE_CXX_STANDARD 14)
+  if (CMAKE_CXX_COMPILER_ID STREQUAL SunPro AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.14)
+    set(CMAKE_CXX_STANDARD 98)
   else()
-    set(CMAKE_CXX_STANDARD 11)
+    include(${CMake_SOURCE_DIR}/Source/Checks/cm_cxx14_cstdio.cmake)
+    if(NOT CMake_CXX14_CSTDIO_BROKEN)
+      set(CMAKE_CXX_STANDARD 14)
+    else()
+      set(CMAKE_CXX_STANDARD 11)
+    endif()
   endif()
 endif()
 if(NOT CMake_TEST_EXTERNAL_CMAKE)

CompileFlags.cmake

@@ -61,7 +61,14 @@ endif()
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL SunPro)
   if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++03")
+    if (NOT CMAKE_CXX_STANDARD OR CMAKE_CXX_STANDARD EQUAL 98)
+      set(CMAKE_CXX_FLAGS "${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")
   endif()