*: use void * for printing pointers

On higher warning levels, compilers expect %p printf arguments to be
void *.  Since format string / argument warnings can be useful
otherwise, let's get rid of this noise by sprinkling casts to void *
over printf calls.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/lib/buffer.c b/lib/buffer.c
index 45e2e1c..b689549 100644
--- a/lib/buffer.c
+++ b/lib/buffer.c
@@ -322,7 +322,8 @@
 	      /* This should absolutely never occur. */
 	      zlog_err("%s: corruption detected: iov_small overflowed; "
 		       "head %p, tail %p, head->next %p",
-		       __func__, b->head, b->tail, b->head->next);
+		       __func__, (void *)b->head, (void *)b->tail,
+		       (void *)b->head->next);
 	      iov = XMALLOC(MTYPE_TMP, iov_alloc*sizeof(*iov));
 	      memcpy(iov, small_iov, sizeof(small_iov));
 	    }
diff --git a/lib/stream.c b/lib/stream.c
index c6f20c8..e13da08 100644
--- a/lib/stream.c
+++ b/lib/stream.c
@@ -53,7 +53,7 @@
  */
 #define STREAM_WARN_OFFSETS(S) \
   zlog_warn ("&(struct stream): %p, size: %lu, getp: %lu, endp: %lu\n", \
-             (S), \
+             (void *)(S), \
              (unsigned long) (S)->size, \
              (unsigned long) (S)->getp, \
              (unsigned long) (S)->endp)\
diff --git a/lib/zclient.c b/lib/zclient.c
index 41ecbb6..963c705 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -919,7 +919,7 @@
   length -= ZEBRA_HEADER_SIZE;
 
   if (zclient_debug)
-    zlog_debug("zclient 0x%p command 0x%x \n", zclient, command);
+    zlog_debug("zclient 0x%p command 0x%x \n", (void *)zclient, command);
 
   switch (command)
     {