Sync with upstream OpenBSD.

Also some minor build cleanup.

Change-Id: Ibd20602d7ea45685f0c47fceb00ffd6c7ae35954
diff --git a/libc/dns/include/resolv_private.h b/libc/dns/include/resolv_private.h
index 0dab3d8..9484d0e 100644
--- a/libc/dns/include/resolv_private.h
+++ b/libc/dns/include/resolv_private.h
@@ -398,7 +398,6 @@
 #define res_nisourserver	__res_nisourserver
 #define res_ownok		__res_ownok
 #define res_queriesmatch	__res_queriesmatch
-#define res_randomid		__res_randomid
 #define sym_ntop		__sym_ntop
 #define sym_ntos		__sym_ntos
 #define sym_ston		__sym_ston
@@ -454,7 +453,6 @@
 const char *	p_option(u_long);
 char *		p_secstodate(u_long);
 int		dn_count_labels(const char *);
-u_int		res_randomid(void);
 int		res_nameinquery(const char *, int, int, const u_char *,
 				     const u_char *);
 int		res_queriesmatch(const u_char *, const u_char *,
@@ -503,7 +501,11 @@
 
 __LIBC_HIDDEN__ void res_setnetid(res_state, unsigned);
 __LIBC_HIDDEN__ void res_setmark(res_state, unsigned);
-u_int  res_randomid(void);
+
+// We use the OpenBSD __res_randomid...
+u_int __res_randomid(void);
+// ...but NetBSD calls it res_randomid.
+#define res_randomid __res_randomid
 
 #ifdef __i386__
 # define __socketcall extern __attribute__((__cdecl__))