Add a variable to specify language-wide system include directories

Create a `CMAKE_<LANG>_STANDARD_INCLUDE_DIRECTORIES` variable to specify
system include directories for for `<LANG>` compiler command lines.
This plays a role for include directories as the existing
`CMAKE_<LANG>_STANDARD_LIBRARIES` variable does for link libraries.

2 files changed, 32 insertions, 0 deletions

diff --git a/Source/cmGeneratorTarget.cxx b/Source/cmGeneratorTarget.cxx
index 31fff9f..8859172 100644
--- a/Source/cmGeneratorTarget.cxx
+++ b/Source/cmGeneratorTarget.cxx
@@ -2415,6 +2415,18 @@ std::vector<std::string> cmGeneratorTarget::GetIncludeDirectories(
 
   cmDeleteAll(linkInterfaceIncludeDirectoriesEntries);
 
+  // Add standard include directories for this language.
+  std::string const standardIncludesVar =
+    "CMAKE_" + lang + "_STANDARD_INCLUDE_DIRECTORIES";
+  std::string const standardIncludes =
+    this->Makefile->GetSafeDefinition(standardIncludesVar);
+  std::vector<std::string>::size_type const before = includes.size();
+  cmSystemTools::ExpandListArgument(standardIncludes, includes);
+  for (std::vector<std::string>::iterator i = includes.begin() + before;
+       i != includes.end(); ++i) {
+    cmSystemTools::ConvertToUnixSlashes(*i);
+  }
+
   return includes;
 }
 
diff --git a/Source/cmGlobalGenerator.cxx b/Source/cmGlobalGenerator.cxx
index 3f4c22f..ea2842f 100644
--- a/Source/cmGlobalGenerator.cxx
+++ b/Source/cmGlobalGenerator.cxx
@@ -1385,6 +1385,9 @@ cmGlobalGenerator::CreateQtAutoGeneratorsTargets()
 
 void cmGlobalGenerator::FinalizeTargetCompileInfo()
 {
+  std::vector<std::string> const langs =
+    this->CMakeInstance->GetState()->GetEnabledLanguages();
+
   // Construct per-target generator information.
   for (unsigned int i = 0; i < this->Makefiles.size(); ++i) {
     cmMakefile* mf = this->Makefiles[i];
@@ -1429,6 +1432,23 @@ void cmGlobalGenerator::FinalizeTargetCompileInfo()
         }
       }
     }
+
+    // The standard include directories for each language
+    // should be treated as system include directories.
+    std::set<std::string> standardIncludesSet;
+    for (std::vector<std::string>::const_iterator li = langs.begin();
+         li != langs.end(); ++li) {
+      std::string const standardIncludesVar =
+        "CMAKE_" + *li + "_STANDARD_INCLUDE_DIRECTORIES";
+      std::string const standardIncludesStr =
+        mf->GetSafeDefinition(standardIncludesVar);
+      std::vector<std::string> standardIncludesVec;
+      cmSystemTools::ExpandListArgument(standardIncludesStr,
+                                        standardIncludesVec);
+      standardIncludesSet.insert(standardIncludesVec.begin(),
+                                 standardIncludesVec.end());
+    }
+    mf->AddSystemIncludeDirectories(standardIncludesSet);
   }
 }