Cleanup: fix compiler warnings

source/blender/blenlib/intern/system.c

@@ -128,6 +128,7 @@ static void __cpuid(
       : "a"(selector)
       : "ebx");
 #  else
+  (void)selector;
   data[0] = data[1] = data[2] = data[3] = 0;
 #  endif
 }

source/blender/freestyle/intern/blender_interface/BlenderStrokeRenderer.cpp

@@ -628,7 +628,7 @@ void BlenderStrokeRenderer::GenerateStrokeMesh(StrokeGroup *group, bool hasTex)
   mesh->mloopcol = colors;
 
   mesh->mat = (Material **)MEM_mallocN(sizeof(Material *) * mesh->totcol, "MaterialList");
-  for (const auto &item : group->materials.items()) {
+  for (const auto item : group->materials.items()) {
     Material *material = item.key;
     const int matnr = item.value;
     mesh->mat[matnr] = material;