Unused heap error messages

[Wuerfel21]

Fan favorites such as

LR__1971
	byte	" !!! corrupted heap??? !!! "
	byte	0
LR__1972
	byte	" !!! out of heap memory !!! "
	byte	0
LR__1973
	byte	" !!! corrupted heap !!! "
	byte	0

are generated when the heap allocator is used, even though _gc_errmsg is stubbed out by default, so they just end up being dead weight.

Not 100% on what's the best way to solve this. Low priority as well, I guess