diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 48e76ed..a7644a9 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -457,7 +457,7 @@ MSG
                                   'LDFLAGS' => "#$LDFLAGS #{ldflags}",
                                   'LOCAL_LIBS' => "#$LOCAL_LIBS #$libs",
                                   'LIBS' => "#{librubyarg} #{opt} #$LIBS")
-    conf['LIBPATH'] = libpathflag(libpath.map {|s| RbConfig::expand(s.dup, conf)})
+    conf['LIBPATH'] = libpath.map {|s| LIBPATHFLAG % RbConfig::expand(s.dup, conf).quote}.join("")
     RbConfig::expand(TRY_LINK.dup, conf)
   end