Changes for Mac OS X. Most important is stack sizes in samterm,

which were completely bogus.  (Libthread used to ignore them but
not anymore.  Maybe we really should ignore them, but that breaks
Venti, which needs *really* big stacks.)

src/cmd/sam/sam.h

@@ -16,6 +16,7 @@
 #define	TRUE		1
 #define	FALSE		0
 
+#undef INFINITY	/* Darwin declares this as HUGE_VAL */
 #define	INFINITY	0x7FFFFFFFL
 #define	INCR		25
 #define	STRSIZE		(2*BLOCKSIZE)