New bootspec "gpt_disk_guid=", new -as mkisofs option --gpt_disk_guid, new -report_system_area mode "make_guid"

xorriso/xorriso.texi

@@ -50,7 +50,7 @@
 @c man .\" First parameter, NAME, should be all caps
 @c man .\" Second parameter, SECTION, should be 1-8, maybe w/ subsection
 @c man .\" other parameters are allowed: see man(7), man(1)
-@c man .TH XORRISO 1 "Version 1.4.5, Aug 07, 2016"
+@c man .TH XORRISO 1 "Version 1.4.5, Aug 12, 2016"
 @c man .\" Please adjust this date whenever revising the manpage.
 @c man .\"
 @c man .\" Some roff macros, for reference:
@@ -3893,6 +3893,20 @@ a disk file but nevertheless causes adjustments in the
 loaded system area data. Such adjustments may get ordered by -boot_image
 commands.
 @*
+@cindex GPT, control GUID, -boot_image gpt_disk_guid=
+@strong{-boot_image any gpt_disk_guid=}value controls whether an emerging GPT
+shall get a randomly generated disk GUID or whether the GUID is supplied by
+the user.
+Value "random" is default. Value "volume_date_uuid" produces a low quality
+GUID from the value set by -volume_date "uuid".
+@*
+A string of 32 hex digits, or a RFC 4122 compliant GUID string may be used to
+set the disk GUID directly.
+@*
+E.g. gpt_disk_guid=2303cd2a-73c7-424a-a298-25632da7f446
+@*
+The partition GUIDs get generated by minimally varying the disk GUID.
+@*
 @strong{-boot_image any part_like_isohybrid=on} enables
 -boot_image isolinux partition_entry= even if no
 -boot_image isolinux system_area= is given.
@@ -4782,6 +4796,9 @@ With mode @strong{gpt_crc_of:}disk_path read up to 32 KiB from the disk
 file with the path given after the colon. Compute the GPT compliant CRC number
 and print it to the result channel. The number is shown like "0x690fd979".
 The special disk_path "-" causes reading from standard input.
+@*
+With mode @strong{make_guid} print a pseudo-random GUID in RFC 4122 format
+to result channel.
 @end table
 @c man .TP
 @c man .B Navigation in ISO image and disk filesystem: