test/Makefile.os2: wlib must run case-sensitively.
diff --git a/test/Makefile.os2 b/test/Makefile.os2
index 7676369..922dffa 100644
--- a/test/Makefile.os2
+++ b/test/Makefile.os2
@@ -55,7 +55,7 @@
 .c: ../src/test
 
 $(TESTLIB): $(COBJS)
-  wlib -q -b -n $@ $(COBJS)
+  wlib -q -b -n -c $@ $(COBJS)
 
 .obj.exe:
   @%make $(TESTLIB)