Define MAXHOSTNAMELEN explicitly in source files.

Bug: 19093777
Bug: 19092844
Change-Id: I0778507ca2d5c008abb9a6d6315d0909263a8817
diff --git a/libc/include/sys/param.h b/libc/include/sys/param.h
index 03a462e..e64d6ce 100644
--- a/libc/include/sys/param.h
+++ b/libc/include/sys/param.h
@@ -29,8 +29,8 @@
 #define _SYS_PARAM_H_
 
 #include <limits.h>
+#include <linux/param.h>
 
-#define HZ 100
 #define MAXPATHLEN  PATH_MAX
 #define MAXSYMLINKS 8