Features: On SunPro link with language standard compiler flag

When C++ feature requirements or `CXX_STANDARD` cause us to compile
on SunPro with the `-std=c++11` option, link with the option too.
This is needed to make the compiler use the matching standard library.

Modules/Compiler/SunPro-CXX.cmake

@@ -36,6 +36,7 @@ if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)
   set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "")
   set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "-std=c++11")
   set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "-std=c++11")
+  set(CMAKE_CXX_LINK_WITH_STANDARD_COMPILE_OPTION 1)
 endif()
 
 if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.13)

Source/cmLocalGenerator.cxx

@@ -1321,6 +1321,15 @@ void cmLocalGenerator::AddLanguageFlagsForLinking(
   std::string& flags, cmGeneratorTarget const* target, const std::string& lang,
   const std::string& config)
 {
+  if (this->Makefile->IsOn("CMAKE_" + lang +
+                           "_LINK_WITH_STANDARD_COMPILE_OPTION")) {
+    // This toolchain requires use of the language standard flag
+    // when linking in order to use the matching standard library.
+    // FIXME: If CMake gains an abstraction for standard library
+    // selection, this will have to be reconciled with it.
+    this->AddCompilerRequirementFlag(flags, target, lang);
+  }
+
   this->AddLanguageFlags(flags, target, lang, config);
 }