diff --git a/source/i18n/ScriptInterface.cpp b/source/i18n/ScriptInterface.cpp
index 28ab882830..d80971c733 100755
--- a/source/i18n/ScriptInterface.cpp
+++ b/source/i18n/ScriptInterface.cpp
@@ -3,15 +3,7 @@
 #include "ScriptInterface.h"
 #include "CLocale.h"
 #include "StringConvert.h"
-
-#include <jsapi.h>
-
-// Make JS debugging a little easier by automatically naming GC roots
-#ifndef NDEBUG
-// Don't simply #define NAME_ALL_GC_ROOTS, because jsapi.h is horridly broken
-# define JS_AddRoot(cx, rp) JS_AddNamedRoot((cx), (rp), __FILE__)
-#endif
-
+#include "scripting/SpiderMonkey.h"
 
 #include "ps/CLogger.h"
 #define LOG_CATEGORY "i18n"
diff --git a/source/ps/Singleton.h b/source/ps/Singleton.h
index 01ba14c63c..66f6786303 100755
--- a/source/ps/Singleton.h
+++ b/source/ps/Singleton.h
@@ -19,10 +19,6 @@
 #ifndef _TEMPLATE_SINGLETON
 #define _TEMPLATE_SINGLETON
 
-#include <assert.h>
-#include "lib.h"
-
-
 template<typename T>
 class Singleton
 {
@@ -31,7 +27,7 @@ class Singleton
    public:
       Singleton()
       {
-         assert( !ms_singleton );
+         assert2( !ms_singleton );
 
          //use a cunning trick to get the singleton pointing to the start of
          //the whole, rather than the start of the Singleton part of the object
diff --git a/source/ps/StringConvert.cpp b/source/ps/StringConvert.cpp
index 69418c1fed..d277462f2d 100755
--- a/source/ps/StringConvert.cpp
+++ b/source/ps/StringConvert.cpp
@@ -5,7 +5,7 @@
 
 #include <assert.h>
 
-#include <jsapi.h>
+#include "scripting/SpiderMonkey.h"
 
 #if SDL_BYTE_ORDER == SDL_BIG_ENDIAN
 #define ucs2le_to_wchart(ptr) (wchar_t)( (u16) ((u8*)ptr)[0] | (u16) ( ((u8*)ptr)[1] << 8) )
diff --git a/source/scripting/ScriptableComplex.h b/source/scripting/ScriptableComplex.h
index f509e5985a..20baa37fae 100644
--- a/source/scripting/ScriptableComplex.h
+++ b/source/scripting/ScriptableComplex.h
@@ -6,7 +6,7 @@
 #include "scripting/ScriptingHost.h"
 #include "JSConversions.h"
 
-#include <jsatom.h>
+#include "scripting/SpiderMonkey.h"
 
 #include <set>
 
diff --git a/source/scripting/ScriptingHost.h b/source/scripting/ScriptingHost.h
index 082fdf4f83..9295f48e99 100755
--- a/source/scripting/ScriptingHost.h
+++ b/source/scripting/ScriptingHost.h
@@ -26,17 +26,7 @@ ERROR_SUBGROUP(Scripting, DefineType);
 ERROR_TYPE(Scripting_DefineType, AlreadyExists);
 ERROR_TYPE(Scripting_DefineType, CreationFailed);
 
-#include <jsapi.h>
-
-#ifndef NDEBUG
-#include <jsdbgapi.h>
-#endif
-
-// Make JS debugging a little easier by automatically naming GC roots
-#ifndef NDEBUG
-// Don't simply #define NAME_ALL_GC_ROOTS, because jsapi.h is horridly broken
-# define JS_AddRoot(cx, rp) JS_AddNamedRoot((cx), (rp), __FILE__ )
-#endif
+#include "scripting/SpiderMonkey.h"
 
 #include <string>
 #include <vector>
diff --git a/source/scripting/SpiderMonkey.h b/source/scripting/SpiderMonkey.h
new file mode 100644
index 0000000000..187b2e74db
--- /dev/null
+++ b/source/scripting/SpiderMonkey.h
@@ -0,0 +1,35 @@
+// master header for the SpiderMonkey Javascript library.
+
+// include this instead of accessing any <js*.h> headers directly.
+// rationale: these headers require an OS macro to be set (XP_*).
+// since this is specific to SpiderMonkey, we don't want to hide the fact in
+// some obscure header that's pulled in via PCH (would make reuse harder).
+// we take care of it below.
+
+// jstypes.h (included via jsapi.h) requires we define
+// "one of XP_BEOS, XP_MAC, XP_OS2, XP_WIN or XP_UNIX".
+#include "config.h"
+#if defined(OS_WIN)
+# define XP_WIN
+#elif defined(OS_MAC)
+# define XP_MAC
+#elif defined(OS_BEOS)
+# define XP_BEOS
+#else
+# define XP_UNIX
+#endif
+
+#include <jsapi.h>
+#include <jsatom.h>
+#ifndef NDEBUG
+# include <jsdbgapi.h>
+#endif
+
+// include any further required headers here
+
+
+// Make JS debugging a little easier by automatically naming GC roots
+// Don't simply #define NAME_ALL_GC_ROOTS, because jsapi.h is horridly broken
+#ifndef NDEBUG
+# define JS_AddRoot(cx, rp) JS_AddNamedRoot((cx), (rp), __FILE__ )
+#endif