diff --git a/Source/CMakeLists.txt b/Source/CMakeLists.txt
index 55d09d14..cccb2c60 100644
--- a/Source/CMakeLists.txt
+++ b/Source/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.10.0)
-project(moja VERSION 1.0.6 LANGUAGES CXX)
+project(moja VERSION 1.0.6 LANGUAGES CXX C)
 
 #turn on using solution folders
 set_property( GLOBAL PROPERTY USE_FOLDERS ON)
diff --git a/Source/moja.flint/include/moja/flint/writesystemconfig.h b/Source/moja.flint/include/moja/flint/writesystemconfig.h
index ccae118b..a567be07 100644
--- a/Source/moja.flint/include/moja/flint/writesystemconfig.h
+++ b/Source/moja.flint/include/moja/flint/writesystemconfig.h
@@ -4,6 +4,7 @@
 #include <moja/flint/modulebase.h>
 
 #include <boost/iostreams/stream_buffer.hpp>
+#include <Poco/Mutex.h>
 
 namespace moja {
 namespace flint {
diff --git a/Source/moja.flint/include/moja/flint/writevariablegrid.h b/Source/moja.flint/include/moja/flint/writevariablegrid.h
index 080efc7b..f6e8d41d 100644
--- a/Source/moja.flint/include/moja/flint/writevariablegrid.h
+++ b/Source/moja.flint/include/moja/flint/writevariablegrid.h
@@ -8,6 +8,7 @@
 #include "moja/flint/modulebase.h"
 
 #include <boost/algorithm/string.hpp>
+#include <Poco/Mutex.h>
 
 #include <algorithm>
 #include <unordered_map>