OS X: Use -iframework for system framework directories

Just like -I flag has its -isystem counterpart which marks an include
directory as a system directory and prevents unwanted warnings, on Apple
systems there is -iframework -- a system directory replacement for -F.
Use this flag to implement include_directories(SYSTEM) for frameworks.

Modules/Platform/Darwin-Clang.cmake

@@ -24,4 +24,7 @@ macro(__darwin_compiler_clang lang)
   set(CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS "-bundle -Wl,-headerpad_max_install_names")
   set(CMAKE_${lang}_SYSROOT_FLAG "-isysroot")
   set(CMAKE_${lang}_OSX_DEPLOYMENT_TARGET_FLAG "-mmacosx-version-min=")
+  if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 3.1)
+    set(CMAKE_${lang}_SYSTEM_FRAMEWORK_SEARCH_FLAG "-iframework ")
+  endif()
 endmacro()

Modules/Platform/Darwin-GNU.cmake

@@ -23,6 +23,10 @@ macro(__darwin_compiler_gnu lang)
   # GNU does not have -shared on OS X
   set(CMAKE_SHARED_LIBRARY_CREATE_${lang}_FLAGS "-dynamiclib -Wl,-headerpad_max_install_names")
   set(CMAKE_SHARED_MODULE_CREATE_${lang}_FLAGS "-bundle -Wl,-headerpad_max_install_names")
+
+  if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4.3)
+    set(CMAKE_${lang}_SYSTEM_FRAMEWORK_SEARCH_FLAG "-iframework ")
+  endif()
 endmacro()
 
 macro(cmake_gnu_set_sysroot_flag lang)

Source/cmLocalGenerator.cxx

@@ -1344,6 +1344,12 @@ std::string cmLocalGenerator::GetIncludeFlags(
   const char* fwSearchFlag =
     this->Makefile->GetDefinition(fwSearchFlagVar);
 
+  std::string sysFwSearchFlagVar = "CMAKE_";
+  sysFwSearchFlagVar += lang;
+  sysFwSearchFlagVar += "_SYSTEM_FRAMEWORK_SEARCH_FLAG";
+  const char* sysFwSearchFlag =
+    this->Makefile->GetDefinition(sysFwSearchFlagVar);
+
   bool flagUsed = false;
   std::set<std::string> emitted;
 #ifdef __APPLE__
@@ -1360,9 +1366,17 @@ std::string cmLocalGenerator::GetIncludeFlags(
       frameworkDir = cmSystemTools::CollapseFullPath(frameworkDir.c_str());
       if(emitted.insert(frameworkDir).second)
         {
-        includeFlags
-          << fwSearchFlag << this->Convert(frameworkDir,
-                                           START_OUTPUT, shellFormat, true)
+        if (sysFwSearchFlag && target &&
+            target->IsSystemIncludeDirectory(*i, config))
+          {
+          includeFlags << sysFwSearchFlag;
+          }
+        else
+          {
+          includeFlags << fwSearchFlag;
+          }
+        includeFlags << this->Convert(frameworkDir, START_OUTPUT,
+                                      shellFormat, true)
           << " ";
         }
       continue;