As far as I can tell from my hilfe input, I'm only running one. ;)
The internals of the library are given from the programs using it, as far as I can tell. You feed it a superstructure (struct jpeg_compress_struct).
Increasing the default buffer size (it's supposed to ask for more if needed) at least stopped it from triggering the bug. :p
-#define DEFAULT_BUF_SIZE 8192 +#define DEFAULT_BUF_SIZE 81920
Probably not the correct solution though.