diff --git a/reactos/tools/rbuild/backend/mingw/mingw.cpp b/reactos/tools/rbuild/backend/mingw/mingw.cpp
index c5f78d7b978..fc81eb31008 100644
--- a/reactos/tools/rbuild/backend/mingw/mingw.cpp
+++ b/reactos/tools/rbuild/backend/mingw/mingw.cpp
@@ -499,8 +499,8 @@ MingwBackend::GenerateGlobalVariables () const
 		if ( ModuleHandlerInformations[i].cflags && ModuleHandlerInformations[i].cflags[0] )
 		{
 				fprintf ( fMakefile,
-						  "MODULETYPE%zd_%sFLAGS:=%s\n",
-						  i,
+						  "MODULETYPE%d_%sFLAGS:=%s\n",
+						  (int)i,
 						  "C",
 						  ModuleHandlerInformations[i].cflags );
 		}
@@ -508,8 +508,8 @@ MingwBackend::GenerateGlobalVariables () const
 		if ( ModuleHandlerInformations[i].cflags && ModuleHandlerInformations[i].cflags[0] )
 		{
 				fprintf ( fMakefile,
-						  "MODULETYPE%zd_%sFLAGS:=%s\n",
-						  i,
+						  "MODULETYPE%d_%sFLAGS:=%s\n",
+						  (int)i,
 						  "CXX",
 						  ModuleHandlerInformations[i].cflags );
 		}
@@ -517,8 +517,8 @@ MingwBackend::GenerateGlobalVariables () const
 		if ( ModuleHandlerInformations[i].nasmflags && ModuleHandlerInformations[i].nasmflags[0] )
 		{
 				fprintf ( fMakefile,
-						  "MODULETYPE%zd_%sFLAGS:=%s\n",
-						  i,
+						  "MODULETYPE%d_%sFLAGS:=%s\n",
+						  (int)i,
 						  "NASM",
 						  ModuleHandlerInformations[i].nasmflags );
 		}