Better fix for #68601 for perf
https://bitbucket.org/libgd/gd-libgd/commits/81e9a993f2893d651d225646378e3fd1b7465467
Merge branch 'PHP-5.5' into PHP-5.6

* PHP-5.5:
  Better fix for #68601 for perf https://bitbucket.org/libgd/gd-libgd/commits/81e9a993f2893d651d225646378e3fd1b7465467
Merge branch 'PHP-5.6'

* PHP-5.6:
  Better fix for #68601 for perf https://bitbucket.org/libgd/gd-libgd/commits/81e9a993f2893d651d225646378e3fd1b7465467