Merge branch 'PHP-5.6' into PHP-7.0

diff --cc NEWS
index 10dbc79eb74c517f25dc92ff8abe3ea9bcdc6a59,a7a71846bb200544d4ad9abf91dee611bc809ef0..46fddef86f265887f42495c5ed70b84c335752db
--- 1/NEWS
--- 2/NEWS
+++ b/NEWS
@@@ -32,10 -28,12 +32,12 @@@ PH
      (Mark Plomer, cmb)
    . Fixed bug #73157 (imagegd2() ignores 3rd param if 4 are given). (cmb)
    . Fixed bug #73155 (imagegd2() writes wrong chunk sizes on boundaries). (cmb)
+   . Fixed bug #73159 (imagegd2(): unrecognized formats may result in corrupted
+     files). (cmb)
  
  - Mbstring:
 -  . Fixed bug #72994 (mbc_to_code() out of bounds read). (Laruence, cmb)
 -  . Fixed bug #66964 (mb_convert_variables() cannot detect recursion). (Yasuo)
 +  . Fixed bug #66797 (mb_substr only takes 32-bit signed integer). (cmb)
 +  . Fixed bug #66964 (mb_convert_variables() cannot detect recursion) (Yasuo)
    . Fixed bug #72992 (mbstring.internal_encoding doesn't inherit default_charset).
      (Yasuo)