msvcm80: Add stub RegisterModuleUninitializer function.

dlls/msvcm80/msvcm80.spec

 @ stub -arch=win32 ?DoCallBackInDefaultDomain@<CrtImplementationDetails>@@YAXP6GJPAX@Z0@Z
 @ stub -arch=win64 ?DoCallBackInDefaultDomain@<CrtImplementationDetails>@@YAXP6AJPEAX@Z0@Z
 @ cdecl ?DoDllLanguageSupportValidation@<CrtImplementationDetails>@@YAXXZ() CrtImplementationDetails_DoDllLanguageSupportValidation
-@ stub -arch=win32 ?RegisterModuleUninitializer@<CrtImplementationDetails>@@YAXP$AAVEventHandler@System@@@Z
-@ stub -arch=win64 ?RegisterModuleUninitializer@<CrtImplementationDetails>@@YAXPE$AAVEventHandler@System@@@Z
+@ cdecl -arch=win32 ?RegisterModuleUninitializer@<CrtImplementationDetails>@@YAXP$AAVEventHandler@System@@@Z(ptr) CrtImplementationDetails_RegisterModuleUninitializer
+@ cdecl -arch=win64 ?RegisterModuleUninitializer@<CrtImplementationDetails>@@YAXPE$AAVEventHandler@System@@@Z(ptr) CrtImplementationDetails_RegisterModuleUninitializer
 @ stub -arch=win32 ?ThrowModuleLoadException@<CrtImplementationDetails>@@YAXP$AAVString@System@@@Z
 @ stub -arch=win64 ?ThrowModuleLoadException@<CrtImplementationDetails>@@YAXPE$AAVString@System@@@Z
 @ stub -arch=win32 ?ThrowModuleLoadException@<CrtImplementationDetails>@@YAXP$AAVString@System@@P$AAVException@3@@Z

dlls/msvcm80/msvcm80_main.c

@@ -43,3 +43,9 @@ void __cdecl CrtImplementationDetails_DoDllLanguageSupportValidation(void)
 {
     FIXME("stub\n");
 }
+
+/* void __cdecl <CrtImplementationDetails>::RegisterModuleUninitializer(System.EventHandler^) */
+void __cdecl CrtImplementationDetails_RegisterModuleUninitializer(void* handler)
+{
+    FIXME("%p: stub\n", handler);
+}