[lkrnprefix] Include iPXE version string in image header

Originally-implemented-by: Christian Hesse <list@eworm.de>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/arch/i386/Makefile

 #
 CFLAGS			+= -Ui386
 
+# Define version string for lkrnprefix.S
+#
+CFLAGS_lkrnprefix	+= -DVERSION="\"$(VERSION)\""
+
 # Locations of utilities
 #
 ISOLINUX_BIN_LIST	:= \

src/arch/i386/prefix/lkrnprefix.S

 start_sys:
 	.word	0
 kernel_version:
-	.word	0
+	.word	version_string - 0x200
 type_of_loader:
 	.byte	0
 loadflags:
 hardware_subarch_data:
 	.byte	0, 0, 0, 0, 0, 0, 0, 0
 
+version_string:
+	.asciz	VERSION
+
 /*
 	We don't need to do too much setup.