diff --git a/apps/openmw-mp/Script/CTypes.h b/apps/openmw-mp/Script/CTypes.h
index f540a7fb9..a525d9755 100644
--- a/apps/openmw-mp/Script/CTypes.h
+++ b/apps/openmw-mp/Script/CTypes.h
@@ -12,7 +12,7 @@ typedef unsigned __int64 RetType;
 #else
 typedef unsigned long long RetType;
 #endif
-#elif defined __x86_64__ && defined __ILP32__
+#elif (defined __x86_64__ || defined __aarch64__) && defined __ILP32__
 typedef unsigned long long RetType;
 #else
 typedef unsigned long RetType;
@@ -23,6 +23,6 @@ typedef unsigned int PlayerId;
 
 #define InvalidPID ((unsigned int) -1)
 
-#if !defined __cplusplus
+#if !(defined __cplusplus || defined __genffi__)
 typedef uint8_t bool;
 #endif
diff --git a/apps/openmw-mp/Script/Platform.h b/apps/openmw-mp/Script/Platform.h
index 59fc24290..2d6dff66a 100644
--- a/apps/openmw-mp/Script/Platform.h
+++ b/apps/openmw-mp/Script/Platform.h
@@ -17,7 +17,7 @@
 #endif
 #endif
 
-#if defined _WIN32 && !defined _LUAJIT_PREPROCESS
+#if defined _WIN32 && !defined __genffi__
 #ifndef CDECL
 #define CDECL __cdecl
 #endif
@@ -39,13 +39,13 @@
 #define IMPORT_FUNCTION EXTERN
 #endif
 
-#if defined _LUAJIT_PREPROCESS
+#if defined __genffi__
 #define API_FUNCTION
 #elif !defined _HOST
 #define API_FUNCTION IMPORT_FUNCTION
 #else
 #define API_FUNCTION EXPORT_FUNCTION
-#endif // _LUAJIT_PREPROCESS
+#endif // __genffi__
 
 #if defined __cplusplus
 #define NAMESPACE_BEGIN(name) namespace name {
diff --git a/apps/openmw-mp/Script/api.h b/apps/openmw-mp/Script/api.h
index 76120b452..477d83d48 100644
--- a/apps/openmw-mp/Script/api.h
+++ b/apps/openmw-mp/Script/api.h
@@ -15,7 +15,7 @@
 
 #include "CTypes.h"
 
-#if !(defined _HOST || defined _LUAJIT_PREPROCESS)
+#if !(defined _HOST || defined __genffi__)
 
 /** @addtogroup PluginCallbacks Plugin Callbacks
  *  @brief Those callbacks can be implemented by plugin.