diff --git a/source/gui/Scripting/JSInterface_GUISize.h b/source/gui/Scripting/JSInterface_GUISize.h
index 61682bfc6c..1f0a13cbe2 100644
--- a/source/gui/Scripting/JSInterface_GUISize.h
+++ b/source/gui/Scripting/JSInterface_GUISize.h
@@ -18,8 +18,9 @@
 #ifndef INCLUDED_JSI_GUISIZE
 #define INCLUDED_JSI_GUISIZE
 
-class CStr8;
-class ScriptInterface;
+#include "ps/CStr.h"
+#include "scriptinterface/ScriptForward.h"
+#include "scriptinterface/ScriptTypes.h"
 
 namespace JSI_GUISize
 {
@@ -33,7 +34,7 @@ namespace JSI_GUISize
 	bool construct(JSContext* cx, uint argc, JS::Value* vp);
 	bool toString(JSContext* cx, uint argc, JS::Value* vp);
 
-	CStr8 ToPercentString(double pix, double per);
+	CStr ToPercentString(double pix, double per);
 }
 
 #endif // INCLUDED_JSI_GUISIZE
diff --git a/source/gui/SettingTypes/CGUISize.cpp b/source/gui/SettingTypes/CGUISize.cpp
index 63b0a9c54c..843d200115 100644
--- a/source/gui/SettingTypes/CGUISize.cpp
+++ b/source/gui/SettingTypes/CGUISize.cpp
@@ -21,6 +21,7 @@
 
 #include "gui/Scripting/JSInterface_GUISize.h"
 #include "ps/CLogger.h"
+#include "ps/CStr.h"
 #include "scriptinterface/Object.h"
 #include "scriptinterface/ScriptInterface.h"
 
@@ -72,7 +73,7 @@ bool CGUISize::FromString(const CStr& Value)
 
 	// Check the input is only numeric
 	const char* input = Value.c_str();
-	CStr buffer = "";
+	CStr buffer;
 	unsigned int coord = 0;
 	float pixels[4] = {0, 0, 0, 0};
 	float percents[4] = {0, 0, 0, 0};
diff --git a/source/lobby/scripting/GlooxScriptConversions.cpp b/source/lobby/scripting/GlooxScriptConversions.cpp
index 91aaf86225..048fd8a113 100644
--- a/source/lobby/scripting/GlooxScriptConversions.cpp
+++ b/source/lobby/scripting/GlooxScriptConversions.cpp
@@ -19,7 +19,7 @@
 
 #include "lib/config2.h"
 #if CONFIG2_LOBBY
-
+#include "lib/utf8.h"
 #include "lobby/XmppClient.h"
 #include "scriptinterface/ScriptConversions.h"
 
diff --git a/source/ps/Mod.h b/source/ps/Mod.h
index 5d5daa95b7..ebf40d495e 100644
--- a/source/ps/Mod.h
+++ b/source/ps/Mod.h
@@ -20,8 +20,7 @@
 
 #include "ps/CStr.h"
 #include "ps/GameSetup/CmdLineArgs.h"
-
-class ScriptContext;
+#include "scriptinterface/ScriptForward.h"
 
 extern std::vector<CStr> g_modsLoaded;
 extern CmdLineArgs g_args;
diff --git a/source/ps/ModIo.h b/source/ps/ModIo.h
index 4cc60e459a..3bfd83c319 100644
--- a/source/ps/ModIo.h
+++ b/source/ps/ModIo.h
@@ -25,9 +25,12 @@
 
 #include "lib/external_libraries/curl.h"
 #include "lib/os_path.h"
+#include "scriptinterface/ScriptForward.h"
 
+#include <map>
 #include <sodium.h>
 #include <string>
+#include <vector>
 
 // TODO: Allocate instance of the below two using sodium_malloc?
 struct PKStruct
diff --git a/source/scriptinterface/ScriptConversions.h b/source/scriptinterface/ScriptConversions.h
index c8c993e8f0..7f98d89b6e 100644
--- a/source/scriptinterface/ScriptConversions.h
+++ b/source/scriptinterface/ScriptConversions.h
@@ -23,6 +23,7 @@
 #include "ScriptExtraHeaders.h" // for typed arrays
 
 #include <limits>
+#include <vector>
 
 namespace Script
 {
diff --git a/source/scriptinterface/tests/test_FunctionWrapper.h b/source/scriptinterface/tests/test_FunctionWrapper.h
index 3bc43bc08c..99f2d7e2a3 100644
--- a/source/scriptinterface/tests/test_FunctionWrapper.h
+++ b/source/scriptinterface/tests/test_FunctionWrapper.h
@@ -18,6 +18,8 @@
 #include "lib/self_test.h"
 
 #include "scriptinterface/FunctionWrapper.h"
+#include "scriptinterface/ScriptContext.h"
+#include "scriptinterface/ScriptInterface.h"
 
 class TestFunctionWrapper : public CxxTest::TestSuite
 {
diff --git a/source/simulation2/serialization/BinarySerializer.cpp b/source/simulation2/serialization/BinarySerializer.cpp
index 603c5feb7d..6a0b4e4196 100644
--- a/source/simulation2/serialization/BinarySerializer.cpp
+++ b/source/simulation2/serialization/BinarySerializer.cpp
@@ -20,8 +20,8 @@
 #include "BinarySerializer.h"
 
 #include "lib/alignment.h"
+#include "lib/utf8.h"
 #include "ps/CLogger.h"
-
 #include "scriptinterface/FunctionWrapper.h"
 #include "scriptinterface/ScriptExtraHeaders.h"
 #include "scriptinterface/ScriptRequest.h"
diff --git a/source/simulation2/serialization/StdDeserializer.cpp b/source/simulation2/serialization/StdDeserializer.cpp
index c41dec6a3f..15d1e56a88 100644
--- a/source/simulation2/serialization/StdDeserializer.cpp
+++ b/source/simulation2/serialization/StdDeserializer.cpp
@@ -20,6 +20,7 @@
 #include "StdDeserializer.h"
 
 #include "lib/byte_order.h"
+#include "lib/utf8.h"
 #include "ps/CLogger.h"
 #include "ps/CStr.h"
 #include "scriptinterface/FunctionWrapper.h"