diff --git a/reactos/tools/rbuild/backend/mingw/mingw.cpp b/reactos/tools/rbuild/backend/mingw/mingw.cpp
index 161e7007dd8..56c5033e35b 100644
--- a/reactos/tools/rbuild/backend/mingw/mingw.cpp
+++ b/reactos/tools/rbuild/backend/mingw/mingw.cpp
@@ -401,9 +401,13 @@ MingwBackend::GenerateGlobalCFlagsAndProperties (
 	for ( i = 0; i < data.properties.size(); i++ )
 	{
 		Property& prop = *data.properties[i];
-		fprintf ( fMakefile, "%s := %s\n",
-			prop.name.c_str(),
-			prop.value.c_str() );
+
+		if (!prop.isInternal)
+		{
+			fprintf ( fMakefile, "%s := %s\n",
+				prop.name.c_str(),
+				prop.value.c_str() );
+		}
 	}
 
 	if ( data.includes.size() || data.defines.size() )
diff --git a/reactos/tools/rbuild/module.cpp b/reactos/tools/rbuild/module.cpp
index a69288a152a..812638f4fd5 100644
--- a/reactos/tools/rbuild/module.cpp
+++ b/reactos/tools/rbuild/module.cpp
@@ -1705,6 +1705,25 @@ Property::Property ( const XMLElement& node_,
 	att = node_.GetAttribute ( "value", true );
 	assert(att);
 	value = att->value;
+
+	att = node_.GetAttribute ( "internal", false );
+	if ( att != NULL )
+	{
+		const char* p = att->value.c_str();
+		if ( !stricmp ( p, "true" ) || !stricmp ( p, "yes" ) )
+			isInternal = true;
+		else if ( !stricmp ( p, "false" ) || !stricmp ( p, "no" ) )
+			isInternal = false;
+		else
+		{
+			throw InvalidAttributeValueException (
+				node_.location,
+				"internal",
+				att->value );
+		}
+	}
+	else
+		isInternal = false;
 }
 
 Property::Property ( const Project& project_,
diff --git a/reactos/tools/rbuild/rbuild.h b/reactos/tools/rbuild/rbuild.h
index 1b6adba0832..e7a5b28735d 100644
--- a/reactos/tools/rbuild/rbuild.h
+++ b/reactos/tools/rbuild/rbuild.h
@@ -658,6 +658,7 @@ public:
 	const Project& project;
 	const Module* module;
 	std::string name, value;
+	bool isInternal;
 
 	Property ( const XMLElement& node_,
 	           const Project& project_,