lib: move TAG_PAIR out of arith.c.

The TAG_PAIR macro is going to be useful outside of the
math module.

* arith.c (TAG_PAIR): Macro removed.

* lib.h (TAG_PAIR): Added here--oh look!--next to the very
similar and related TYPE_PAIR.

1 files changed, 1 insertions, 0 deletions

diff --git a/lib.h b/lib.h
index d95642b1..f1437e53 100644
--- a/lib.h
+++ b/lib.h
@@ -73,6 +73,7 @@ typedef enum type {
 
 #define TYPE_SHIFT 5
 #define TYPE_PAIR(A, B) ((A) << TYPE_SHIFT | (B))
+#define TAG_PAIR(A, B) ((A) << TAG_SHIFT | (B))
 
 typedef enum functype
 {