use forge macros for sources

  forgeurl:          https://github.com/xdebug/xdebug
  forgesource:       https://github.com/xdebug/xdebug/archive/3.5.1/xdebug-3.5.1.tar.gz
  forgesetupargs:    -n xdebug-3.5.1
  archivename:       xdebug-3.5.1
  archiveext:        tar.gz
  archiveurl:        https://github.com/xdebug/xdebug/archive/3.5.1/xdebug-3.5.1.tar.gz
  topdir:            xdebug-3.5.1
  extractdir:        xdebug-3.5.1
  repo:              xdebug
  scm:               git
  tag:               3.5.1
  version:           3.5.1
  forgename:         github
  dist:              .fc35
  (snapshot date is either manually supplied or computed once %{_sourcedir}/%{archivename}.%{archiveext} is available)
drop pear/pecl dependency
use forge macros for sources