diff --git a/Makefile b/Makefile
index c3fd886..7c01f0e 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,9 @@
+MMCFLAGS := -s asm_fast.par.gc.stseg
+
 all: aoc
 
 aoc: $(wildcard *.m)
-	nix shell nixpkgs#mercury -c mmc --make aoc
+	nix shell nixpkgs#mercury -c mmc $(MMCFLAGS) --make aoc
 
 clean:
 	rm -rf Mercury