use custom runtime

flap/questions/retrolixToX86_64/Makefile

@@ -18,7 +18,9 @@ interpret: build
 compilo: build
 	@for f in $(wildcard *.$(TARGET)); do \
 		printf "%s: " $$f; \
-		./$(FLAP) -t elf $$f && \
+		./$(FLAP) -t x86-64 $$f && \
+		gcc -no-pie -o $${f%.*}.elf $${f%.*}.s runtime.c && \
 		./$${f%.*}.elf; \
+		rm $${f%.*}.s; \
 		printf "\n"; \
 	done

flap/questions/retrolixToX86_64/runtime.c

@@ -0,0 +1,13 @@
+#include <stdint.h>
+#include <stdio.h>
+
+int64_t add_eight_int(int64_t i1, int64_t i2, int64_t i3, int64_t i4,
+                      int64_t i5, int64_t i6, int64_t i7, int64_t i8) {
+  return i1 + i2 + i3 + i4 + i5 + i6 + i7 + i8;
+}
+
+int64_t observe_int(int64_t n) {
+  printf("%ld", n);
+
+  return n;
+}