diff --git a/apps/openmw-mp/CMakeLists.txt b/apps/openmw-mp/CMakeLists.txt
index 2219de99b..0f39ab7d5 100644
--- a/apps/openmw-mp/CMakeLists.txt
+++ b/apps/openmw-mp/CMakeLists.txt
@@ -1,9 +1,10 @@
 project(openmw-mp)
 
-add_subdirectory(amx)
-
 option(BUILD_WITH_PAWN "Enable Pawn language" OFF)
 if(BUILD_WITH_PAWN)
+
+    add_subdirectory(amx)
+
     #set(Pawn_ROOT ${CMAKE_SOURCE_DIR}/external/pawn/)
     set(Pawn_INCLUDES ${Pawn_ROOT}/include)
     set(Pawn_LIBRARY ${Pawn_ROOT}/lib/libamx.a)
diff --git a/apps/openmw-mp/Script/LangNative/LangNative.cpp b/apps/openmw-mp/Script/LangNative/LangNative.cpp
index f2ba91c41..d5f8f27a5 100644
--- a/apps/openmw-mp/Script/LangNative/LangNative.cpp
+++ b/apps/openmw-mp/Script/LangNative/LangNative.cpp
@@ -30,7 +30,7 @@ void LangNative::LoadProgram(const char *filename)
 
     fclose(file);
 
-#ifdef __WIN32__
+#ifdef _WIN32
     lib = LoadLibrary(filename);
 #else
     lib = dlopen(filename, RTLD_LAZY);
@@ -58,7 +58,7 @@ void LangNative::LoadProgram(const char *filename)
 
 int LangNative::FreeProgram()
 {
-#ifdef __WIN32__
+#ifdef _WIN32
     FreeLibrary(lib);
 #else
     dlclose(lib);
diff --git a/apps/openmw-mp/Script/Script.cpp b/apps/openmw-mp/Script/Script.cpp
index 5d2267432..a9240d31b 100644
--- a/apps/openmw-mp/Script/Script.cpp
+++ b/apps/openmw-mp/Script/Script.cpp
@@ -25,7 +25,7 @@ Script::Script(const char *path)
 
     fclose(file);
 
-#ifdef __WIN32__
+#ifdef _WIN32
     if (strstr(path, ".dll"))
 #else
     if (strstr(path, ".so"))
diff --git a/apps/openmw-mp/Script/SystemInterface.hpp b/apps/openmw-mp/Script/SystemInterface.hpp
index 9efd06fd3..52ef9a72d 100644
--- a/apps/openmw-mp/Script/SystemInterface.hpp
+++ b/apps/openmw-mp/Script/SystemInterface.hpp
@@ -5,7 +5,7 @@
 #ifndef PLUGINSYSTEM3_SYSTEMINTERFACE_HPP
 #define PLUGINSYSTEM3_SYSTEMINTERFACE_HPP
 
-#ifdef __WIN32__
+#ifdef _WIN32
 #include <winsock2.h>
 #else
 #include <dlfcn.h>
@@ -14,7 +14,7 @@
 template<typename R = void*>
 struct SystemInterface
 {
-#ifdef __WIN32__
+#ifdef _WIN32
     typedef HMODULE lib_t;
 #else
     typedef void* lib_t;
@@ -23,19 +23,21 @@ struct SystemInterface
     union
     {
         R result;
-#ifdef __WIN32__
+#ifdef _WIN32
         decltype(GetProcAddress(lib_t(), nullptr)) data;
 #else
         decltype(dlsym(lib_t(), nullptr)) data;
 #endif
     };
 
+#ifndef _WIN32
     static_assert(sizeof(result) == sizeof(data), "R should have the same size");
+#endif
 
     SystemInterface() : data(nullptr) {}
     explicit operator bool() { return data; }
 
-#ifdef __WIN32__
+#ifdef _WIN32
     SystemInterface(lib_t handle, const char* name) : data(GetProcAddress(handle, name)) {}
 #else
     SystemInterface(lib_t handle, const char* name) : data(dlsym(handle, name)) {}
diff --git a/apps/openmw-mp/main.cpp b/apps/openmw-mp/main.cpp
index ba226c8b9..8be5ba8a0 100644
--- a/apps/openmw-mp/main.cpp
+++ b/apps/openmw-mp/main.cpp
@@ -17,7 +17,7 @@ void printVersion(string version, int protocol)
 {
     cout << "TES3:MP dedicated server " << version;
     cout << " (";
-#ifdef __WIN32__
+#ifdef _WIN32
     cout << "Windows";
 #elif __linux
     cout << "Linux";