fixed Fix #66590, which may segfault

ext/gd/libgd/webpimg.c

@@ -789,6 +789,7 @@ WebPResult WebPEncode(const uint8* Y,
 		  return webp_failure;
 		}
 		p[new_size - 1] = 0;
+        *p_out = p;
 		*p_out_size_bytes = new_size;
 	  }
 

ext/gd/tests/bug66590_1.phpt

@@ -0,0 +1,17 @@
+--TEST--
+Bug #66590 (imagewebp() doesn't pad to even length) - segfault
+--SKIPIF--
+<?php
+if (!extension_loaded('gd')) die('skip gd extension not available');
+if (!function_exists('imagewebp')) die('skip WebP support not available');
+?>
+--FILE--
+<?php
+$im = imagecreatetruecolor(6, 6);
+ob_start();
+imagewebp($im);
+ob_end_clean();
+echo "ready\n";
+?>
+--EXPECT--
+ready