Prefix semantics have changed

src/arch/i386/prefix/hdprefix.S

+#warning "Needs fixing up for gpxe"
+
+#if 0
+
 /****************************************************************\
 
 hdprefix.S Copyright (C) 2005 Per Dalgas Jakobsen
 		.word BOOTMAGIC
 
 /*** END ********************************************************/
+#endif