https://gcc.gnu.org/ml/gcc-patches/2018-10/msg01676.html
That's now a reality. https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=03385ed3d679cd8125f282697a1c7cf46f8361ccHopefully around the time of DConf next year we'll see GDC included with the release of GCC 9. How cool is that?