[perl-Cairo] Fix building with perl <= 5.14

[Torsten SchÃnfeld <tsch src gnome org>]

commit cfdd10c29739dc4faa31b3de2cb61cd0d190b59e
Author: Torsten SchÃnfeld <kaffeetisch gmx de>
Date:   Wed Oct 3 15:17:36 2012 +0200

    Fix building with perl <= 5.14
    
    The ExtUtils::MakeMaker version shipped with perl <= 5.14 does not seem to
    handle references in the meta information correctly.

 Makefile.PL |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/Makefile.PL b/Makefile.PL
index 9c6aa25..1e374ad 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -52,7 +52,7 @@ my %meta_merge = (
         },
         prereqs => {
           configure => {
-            requires => \%prereqs
+            requires => {%prereqs}, # no direct ref for 5.14 compatibility
           },
           test => {
             recommends => {