Charles Lesire authored Feb 21, 2018 and Anthony Mallet committed Feb 21, 2018

This commit removes mk/sysdep/tinyxml, which now provided by
devel/tinyxml/depend.mk. The package still default to a system package, but is
provided here for convenience.

TinyXML is a simple, small, minimal, C++ XML parser that can be easily
integrating into other programs. It reads XML and creates C++ objects
representing the XML document. The objects can be manipulated, changed, and
saved again as XML.

*Please Note* that TinyXML development has stopped and all development has
moved to TinyXML-2.