Deprecated and disable MY3D loader

I tried to find out about this format, but last info seems to be from 2005 (https://irrlicht.sourceforge.io/forum/viewtopic.php?p=37385)
Website for it no longer exists and I also couldn't find My3DTools on any other place on the web.
We don't even have an example for it in Irrlicht.
Also CMY3DHelper.h introduces quite a bunch of functions and global variables in the irr::core namespace and I'm not really interested in spending time in cleaning this up.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6588 dfc29bdd-3216-0410-991c-e03cc46cb475

changes.txt

@@ -1,6 +1,7 @@
 --------------------------
 Changes in 1.9 (not yet released)
 
+- MY3D loader deprecated and disabled by default as MY3D tools can't be found on the web anymore. Also could always be used as external loader.
 - createCylinderMesh, createArrowMesh and createConeMesh in GeometryCreator tessellation numbers now for full instead of semi-circle.
   Double your tessellation numbers to get same results as in 1.8
   Sorry had to break as old solution didn't allow for odd numbers. Also was documented otherwise, so was a bug.

include/IrrCompileConfig.h

@@ -497,7 +497,11 @@ B3D, MS3D or X meshes */
 #undef _IRR_COMPILE_WITH_LMTS_LOADER_
 #endif
 //! Define _IRR_COMPILE_WITH_MY3D_LOADER_ if you want to load MY3D files
-#define _IRR_COMPILE_WITH_MY3D_LOADER_
+//! Note: As My3DTools can't be found on the web anymore and there hasn't been 
+//! any update about it since around 2005 the loader is deprecated with 
+//! Irrlicht 1.9 and will be removed in Irrlicht 1.10 unless there are any
+//! news about the tool.
+//#define _IRR_COMPILE_WITH_MY3D_LOADER_
 #ifdef NO_IRR_COMPILE_WITH_MY3D_LOADER_
 #undef _IRR_COMPILE_WITH_MY3D_LOADER_
 #endif