Rewrite page(2) references to page(3).

Add description of new libmach.
diff --git a/man/man3/flate.3 b/man/man3/flate.3
index 816875f..7557487 100644
--- a/man/man3/flate.3
+++ b/man/man3/flate.3
@@ -173,7 +173,7 @@
 .I Mkcrctab
 allocates
 (using
-.IR malloc (2)),
+.IR malloc (3)),
 initializes, and returns a table for rapid computation of 32 bit CRC values using the polynomial
 .IR poly .
 .I Blockcrc