Merge branch 'pull-request/2151'

diff --cc UPGRADING
index b874ad6777ad1c2f9fa03a48cf963a631c3459ff,38250ed303a1bd140072bee74b92b5bfe5276f8d..2b4f988370df2daf118d8bc11e78fc73e803ddf8
--- 1/UPGRADING
--- 2/UPGRADING
+++ b/UPGRADING
@@@ -71,6 -70,6 +71,7 @@@ PHP 7.2 UPGRADE NOTE
  
  - GD:
    . Added imagesetclip() and imagegetclip().
++  . Added imageopenpolygon().
  
  - Mbstring:
    . Added mb_chr() and mb_ord().

diff --cc ext/gd/gd.c
Simple merge

diff --cc ext/gd/libgd/gd.c
Simple merge

diff --cc ext/gd/libgd/gd.h
Simple merge