Warning fixes for VS .NET.

src/osgPlugins/txp/trpage_writebuf.cpp

@@ -131,7 +131,7 @@ void trpgMemWriteBuffer::Add(int32 val)
 void trpgMemWriteBuffer::Add(int64 val)
 {
 	if (ness != cpuNess)
-		val = trpg_byteswap_long(val);
+		val = trpg_byteswap_llong(val);
 	append(sizeof(int64),(const char *)&val);
 }