test/Makefile.os2: wlib must run case-sensitively.

Author: sezero

test/Makefile.os2

@@ -55,7 +55,7 @@ LIBS    = SDL2.lib $(TESTLIB)
 .c: ../src/test
 
 $(TESTLIB): $(COBJS)
-  wlib -q -b -n $@ $(COBJS)
+  wlib -q -b -n -c $@ $(COBJS)
 
 .obj.exe:
   @%make $(TESTLIB)