Process generator expressions for 'system' include directories.

Since commit 08cb4fa4 (Process generator expressions in the
INCLUDE_DIRECTORIES property., 2012-09-18), it is possible to use
generator expressions with the include_directories command.

As that command can also have a SYSTEM argument, ensure that the
result of using that argument with generator expressions gives a
sane result.

Source/cmLocalGenerator.cxx

@@ -1212,7 +1212,8 @@ cmLocalGenerator::ConvertToIncludeReference(std::string const& path)
 //----------------------------------------------------------------------------
 std::string cmLocalGenerator::GetIncludeFlags(
                                      const std::vector<std::string> &includes,
-                                     const char* lang, bool forResponseFile)
+                                     const char* lang, bool forResponseFile,
+                                     const char *config)
 {
   if(!lang)
     {
@@ -1285,7 +1286,7 @@ std::string cmLocalGenerator::GetIncludeFlags(
     if(!flagUsed || repeatFlag)
       {
       if(sysIncludeFlag &&
-         this->Makefile->IsSystemIncludeDirectory(i->c_str()))
+         this->Makefile->IsSystemIncludeDirectory(i->c_str(), config))
         {
         includeFlags << sysIncludeFlag;
         }

Source/cmLocalGenerator.h

@@ -149,7 +149,8 @@ public:
   virtual void AppendFlags(std::string& flags, const char* newFlags);
   ///! Get the include flags for the current makefile and language
   std::string GetIncludeFlags(const std::vector<std::string> &includes,
-                              const char* lang, bool forResponseFile = false);
+                              const char* lang, bool forResponseFile = false,
+                              const char *config = 0);
 
   /**
    * Encode a list of preprocessor definitions for the compiler

Source/cmMakefile.cxx

@@ -23,6 +23,7 @@
 #include "cmListFileCache.h"
 #include "cmCommandArgumentParserHelper.h"
 #include "cmDocumentCompileDefinitions.h"
+#include "cmGeneratorExpression.h"
 #include "cmTest.h"
 #ifdef CMAKE_BUILD_WITH_CMAKE
 #  include "cmVariableWatch.h"
@@ -1665,10 +1666,24 @@ cmMakefile::AddSystemIncludeDirectories(const std::set<cmStdString> &incs)
 }
 
 //----------------------------------------------------------------------------
-bool cmMakefile::IsSystemIncludeDirectory(const char* dir)
+bool cmMakefile::IsSystemIncludeDirectory(const char* dir, const char *config)
 {
-  return (this->SystemIncludeDirectories.find(dir) !=
-          this->SystemIncludeDirectories.end());
+  for (std::set<cmStdString>::const_iterator
+      it = this->SystemIncludeDirectories.begin();
+      it != this->SystemIncludeDirectories.end(); ++it)
+    {
+    cmListFileBacktrace lfbt;
+    cmGeneratorExpression ge(lfbt);
+
+    std::vector<std::string> incs;
+    cmSystemTools::ExpandListArgument(ge.Parse(*it)
+                                       ->Evaluate(this, config, false), incs);
+    if (std::find(incs.begin(), incs.end(), dir) != incs.end())
+      {
+      return true;
+      }
+    }
+  return false;
 }
 
 void cmMakefile::AddDefinition(const char* name, const char* value)

Source/cmMakefile.h

@@ -547,7 +547,7 @@ public:
    * Mark include directories as system directories.
    */
   void AddSystemIncludeDirectories(const std::set<cmStdString> &incs);
-  bool IsSystemIncludeDirectory(const char* dir);
+  bool IsSystemIncludeDirectory(const char* dir, const char *config);
 
   /** Expand out any arguements in the vector that have ; separated
    *  strings into multiple arguements.  A new vector is created