swig-pl: Fix when configure is passed --enable-sqlite-compatibility-version

* subversion/bindings/swig/perl/native/Makefile.PL.in
  ($cppflags, $cflags): Set from autoconf with here documents to avoid quoting
    issues.

Patch by: James McCoy <jamessan{_AT_}debian.org>



git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1559009 13f79535-47bb-0310-9956-ffa450edef68