py, unix: Trace root pointers with native emitter under unix port.
Native code has GC-heap pointers in it so it must be scanned. But on
unix port memory for native functions is mmap'd, and so it must have
explicit code to scan it for root pointers.
diff --git a/py/mpconfig.h b/py/mpconfig.h
index 541f7c7..5718ffa 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -569,6 +569,9 @@
#define MICROPY_MAKE_POINTER_CALLABLE(p) (p)
#endif
+// If these MP_PLAT_* macros are overridden then the memory allocated by them
+// must be somehow reachable for marking by the GC, since the native code
+// generators store pointers to GC managed memory in the code.
#ifndef MP_PLAT_ALLOC_EXEC
#define MP_PLAT_ALLOC_EXEC(min_size, ptr, size) do { *ptr = m_new(byte, min_size); *size = min_size; } while(0)
#endif