Add tool that lets us more easily compare compilation paths.

Compare:
IR -> C -> x64
vs.
IR -> x64

examples/sysir/samples.janet

@@ -57,11 +57,11 @@
 (defsys test_arrays:myvec [a:myvec b:myvec]
   (return (+ a b)))
 
-(defsys make_array:myvec []
+'(defsys make_array:myvec []
   (def vec:myvec [0 0 0 0])
   (return vec))
 
-(defsys make_mat:mymat []
+'(defsys make_mat:mymat []
   (def mat:mymat [[1 0 0 0] [0 1 0 0] [0 0 1 0] [0 0 0 1]])
   (return mat))
 

examples/sysir/x64.janet

@@ -0,0 +1,25 @@
+(use ./frontend)
+
+(defn-external printf:int [fmt:pointer x:int])
+(defn-external exit:void [x:int])
+
+(defsys doloop [x:int y:int]
+  (var i:int x)
+  #(printf "i = %d\n" i)
+  (while (< i y)
+    (set i (+ 1 i))
+    (printf "i = %d\n" i))
+  (return x))
+
+(defsys _start:void []
+  (doloop 10 20)
+  (exit (the int 0))
+  (return))
+
+(defn main [& args]
+  (def [_ what] args)
+  (dump)
+  (eprint "MODE: " what)
+  (case what
+    "c" (dumpc)
+    "x64" (dumpx64)))