Cleanup: Silence strict compiler warning

Was happening when using OSD for modifiers.

source/blender/modifiers/intern/MOD_multires.c

@@ -67,6 +67,8 @@ static void initData(ModifierData *md)
 	mmd->quality = 3;
 }
 
+#ifndef WITH_OPENSUBDIV_MODIFIER
+
 static DerivedMesh *applyModifier_DM(
         ModifierData *md, const ModifierEvalContext *ctx,
         DerivedMesh *dm)
@@ -146,6 +148,8 @@ static DerivedMesh *applyModifier_DM(
 
 applyModifier_DM_wrapper(applyModifier, applyModifier_DM)
 
+#endif
+
 #ifdef WITH_OPENSUBDIV_MODIFIER
 
 /* Subdivide into fully qualified mesh. */

source/blender/modifiers/intern/MOD_subsurf.c

@@ -99,6 +99,8 @@ static bool isDisabled(const Scene *scene, ModifierData *md, bool useRenderParam
 	return get_render_subsurf_level(&scene->r, levels, useRenderParams != 0) == 0;
 }
 
+#ifndef WITH_OPENSUBDIV_MODIFIER
+
 static DerivedMesh *applyModifier_DM(
         ModifierData *md, const ModifierEvalContext *ctx,
         DerivedMesh *derivedData)
@@ -135,6 +137,8 @@ static DerivedMesh *applyModifier_DM(
 
 applyModifier_DM_wrapper(applyModifier, applyModifier_DM)
 
+#endif
+
 static DerivedMesh *applyModifierEM_DM(
         ModifierData *md, const ModifierEvalContext *ctx,
         struct BMEditMesh *UNUSED(editData),