diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index a0cd26a871..53f647aef1 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -2352,7 +2352,7 @@ MESSAGE
   COMPILE_C = config_string('COMPILE_C') || '$(CC) $(INCFLAGS) $(CPPFLAGS) $(CFLAGS) $(COUTFLAG)$@ -c $<'
   COMPILE_CXX = config_string('COMPILE_CXX') || '$(CXX) $(INCFLAGS) $(CPPFLAGS) $(CXXFLAGS) $(COUTFLAG)$@ -c $<'
   TRY_LINK = config_string('TRY_LINK') ||
-    "$(CC) #{OUTFLAG}conftest $(INCFLAGS) $(CPPFLAGS) " \
+    "$(CC) #{OUTFLAG}conftest#{$EXEEXT} $(INCFLAGS) $(CPPFLAGS) " \
     "$(CFLAGS) $(src) $(LIBPATH) $(LDFLAGS) $(ARCH_FLAG) $(LOCAL_LIBS) $(LIBS)"
   LINK_SO = config_string('LINK_SO') ||
     if CONFIG["DLEXT"] == $OBJEXT