Update php7 package dependencies

packages/php7.rb

@@ -5,10 +5,12 @@ class Php7 < Package
   source_url 'http://php.net/distributions/php-7.1.0.tar.xz'   # software source tarball url
   source_sha1 'c74c920256b9c6873bae696fbb0ec14a02dc8495'       # source tarball sha1 sum
 
-  depends_on 'curl'
+  depends_on 'pkgconfig'
+  depends_on 'zlibpkg'
   depends_on 'libpng'
   depends_on 'libxml2'
   depends_on 'openssl'
+  depends_on 'curl'
   depends_on 'pcre'
 
   def self.build                                               # self.build contains commands needed to build the software from source