configure.in: fix typo

* configure.in (DLDFLAGS): fix typo, missing comma.
  [ruby-core:61429] [Bug #9624]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45340 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.in

@@ -2770,7 +2770,7 @@ if test "$with_dln_a_out" != yes; then
 
   if test "$rb_cv_dlopen" = yes; then
     AS_CASE(["$target_os"],
-      [darwin*] [
+      [darwin*], [
 	for flag in \
 	  "${linker_flag}-undefined${linker_flag:+,}dynamic_lookup" \
 	  "${linker_flag}-multiply_defined${linker_flag:+,}suppress" \