When COM_EXPORT_GRAPHVIZ is enabled, DebugInfo::graphviz uses a char[1000000] as local variable. When this function is called this is allocated on the stack, which has a size of just 1MB on mac and may cause a stack overflow. This patch allocates the memory on the heap and frees the memory at the end of the function. Reviewed By: LazyDodo Differential Revision: https://developer.blender.org/D13628