This is due to a Godot bug which is now fixed in the master branch, but would require
too much work for a short-lived branch such as 2.1. Building release binaries with GCC 6+
will trigger segfaults due to UB when dereferencing pointers with Object::cast_to.
In theory this check should also be made for Windows cross-compilation with MinGW,
but I am more concerned about Linux distros shipping broken binaries than adventurous
cross-compilers hitting a wall.
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