build: Build against system tinyxml
Tested against 2.6.2.
Bugzilla: https://bugs.gentoo.org/252920 Bugzilla: https://bugs.freedesktop.org/33937
Tested against 2.6.2.
Bugzilla: https://bugs.gentoo.org/252920 Bugzilla: https://bugs.freedesktop.org/33937