diff --git a/cli/transmissioncli.c b/cli/transmissioncli.c
index a6126b762..db9784a37 100644
--- a/cli/transmissioncli.c
+++ b/cli/transmissioncli.c
@@ -127,13 +127,13 @@ int main( int argc, char ** argv )
         printf( "tracker:  %s:%d\n",
                 info->trackerAddress, info->trackerPort );
         printf( "announce: %s\n", info->trackerAnnounce );
-        printf( "size:     %lld (%lld * %d + %lld)\n",
+        printf( "size:     %"PRIu64" (%"PRIu64" * %d + %"PRIu64")\n",
                 info->totalSize, info->totalSize / info->pieceSize,
                 info->pieceSize, info->totalSize % info->pieceSize );
         printf( "file(s):\n" );
         for( i = 0; i < info->fileCount; i++ )
         {
-            printf( " %s (%lld)\n", info->files[i].name,
+            printf( " %s (%"PRIu64")\n", info->files[i].name,
                     info->files[i].length );
         }
 
diff --git a/libtransmission/bencode.c b/libtransmission/bencode.c
index fca279816..136f7898f 100644
--- a/libtransmission/bencode.c
+++ b/libtransmission/bencode.c
@@ -163,7 +163,7 @@ static void __bencPrint( benc_val_t * val, int space )
     switch( val->type )
     {
         case TYPE_INT:
-            fprintf( stderr, "int:  %lld\n", val->val.i );
+            fprintf( stderr, "int:  %"PRIu64"\n", val->val.i );
             break;
 
         case TYPE_STR:
@@ -261,7 +261,7 @@ int tr_bencSave( benc_val_t * val, char ** buf, size_t * used, size_t * max )
     switch( val->type )
     {
         case TYPE_INT:
-            if( tr_bencSprintf( buf, used, max, "i%llde", val->val.i ) )
+            if( tr_bencSprintf( buf, used, max, "i%"PRIu64"e", val->val.i ) )
             {
                 return 1;
             }
diff --git a/libtransmission/internal.h b/libtransmission/internal.h
index 351bf7771..efcbcd835 100644
--- a/libtransmission/internal.h
+++ b/libtransmission/internal.h
@@ -49,6 +49,12 @@
 #  include <arpa/inet.h>
 #endif
 
+#ifdef __GNUC__
+#  define UNUSED __attribute__((unused))
+#else
+#  define UNUSED
+#endif
+
 /* We use OpenSSL whenever possible, since it is likely to be more
    optimized and it is ok to use it with a MIT-licensed application.
    Otherwise, we use the included implementation by vi@nwr.jp. */
diff --git a/libtransmission/net.c b/libtransmission/net.c
index b8cf5d360..c8b876d0d 100644
--- a/libtransmission/net.c
+++ b/libtransmission/net.c
@@ -171,7 +171,7 @@ static void resolveRelease( tr_resolve_t * r )
  * Keeps waiting for addresses to resolve, and removes them from the
  * queue once resolution is done.
  **********************************************************************/
-static void resolveFunc( void * unused )
+static void resolveFunc( void * arg UNUSED )
 {
     tr_resolve_t * r;
     struct hostent * host;
diff --git a/libtransmission/tracker.c b/libtransmission/tracker.c
index 54a618d0d..72da90e52 100644
--- a/libtransmission/tracker.c
+++ b/libtransmission/tracker.c
@@ -332,9 +332,9 @@ static void sendQuery( tr_tracker_t * tc )
             "info_hash=%s&"
             "peer_id=%s&"
             "port=%d&"
-            "uploaded=%lld&"
-            "downloaded=%lld&"
-            "left=%lld&"
+            "uploaded=%"PRIu64"&"
+            "downloaded=%"PRIu64"&"
+            "left=%"PRIu64"&"
             "compact=1&"
             "numwant=50&"
             "key=%s"
diff --git a/libtransmission/transmission.h b/libtransmission/transmission.h
index e835810d7..38ca8c2ce 100644
--- a/libtransmission/transmission.h
+++ b/libtransmission/transmission.h
@@ -28,6 +28,9 @@ extern "C" {
 #endif
 
 #include <inttypes.h>
+#ifndef PRIu64
+# define PRIu64 "lld"
+#endif
 
 #define SHA_DIGEST_LENGTH 20
 #ifdef __BEOS__