This patch makes the UUIDs in the XMP header optional, depending on the
setting of the environment variable GS_GENERATE_UUIDS.

If the environment variable GS_GENERATE_UUIDS is set to "0" or "no", it will
not write out the Document UUID field and also will write the Instance ID
field value as "".

Upstream does not want to do this.

See: https://bugs.ghostscript.com/show_bug.cgi?id=698208
diff -ur orig/gnu-ghostscript-9.14.0/devices/vector/gdevpdfe.c aa/gnu-ghostscript-9.14.0/devices/vector/gdevpdfe.c
--- orig/gnu-ghostscript-9.14.0/devices/vector/gdevpdfe.c	2017-07-09 23:30:28.960479189 +0200
+++ gnu-ghostscript-9.14.0/devices/vector/gdevpdfe.c	2017-07-10 01:04:12.252478276 +0200
@@ -620,7 +620,7 @@
         return code;
 
     /* PDF/A XMP reference recommends setting UUID to empty. If not empty must be a URI */
-    if (pdev->PDFA != 0)
+    if (pdev->PDFA != 0 || (getenv("GS_GENERATE_UUIDS") && (strcasecmp(getenv("GS_GENERATE_UUIDS"), "0") == 0 || strcasecmp(getenv("GS_GENERATE_UUIDS"), "no") == 0)))
         instance_uuid[0] = 0x00;
 
     cre_date_time_len = pdf_get_docinfo_item(pdev, "/CreationDate", cre_date_time, sizeof(cre_date_time));
@@ -720,14 +720,17 @@
             pdf_xml_tag_close(s, "rdf:Description");
             pdf_xml_newline(s);
 
-            pdf_xml_tag_open_beg(s, "rdf:Description");
-            pdf_xml_copy(s, " rdf:about=\"\"");
-            pdf_xml_attribute_name(s, "xmlns:xapMM");
-            pdf_xml_attribute_value(s, "http://ns.adobe.com/xap/1.0/mm/");
-            pdf_xml_attribute_name(s, "xapMM:DocumentID");
-            pdf_xml_attribute_value(s, document_uuid);
-            pdf_xml_tag_end_empty(s);
-            pdf_xml_newline(s);
+            if (!getenv("GS_GENERATE_UUIDS") || (strcasecmp(getenv("GS_GENERATE_UUIDS"), "0") != 0 && strcasecmp(getenv("GS_GENERATE_UUIDS"), "no") != 0))
+            {
+                pdf_xml_tag_open_beg(s, "rdf:Description");
+                pdf_xml_copy(s, " rdf:about=\"\"");
+                pdf_xml_attribute_name(s, "xmlns:xapMM");
+                pdf_xml_attribute_value(s, "http://ns.adobe.com/xap/1.0/mm/");
+                pdf_xml_attribute_name(s, "xapMM:DocumentID");
+                pdf_xml_attribute_value(s, document_uuid);
+                pdf_xml_tag_end_empty(s);
+                pdf_xml_newline(s);
+            }
 
             pdf_xml_tag_open_beg(s, "rdf:Description");
             pdf_xml_copy(s, " rdf:about=\"\"");
ref='/guix/log/tests/gnu-maintenance.scm?id=dac4fd03cf9dbace17e3f58aed01ab15a4d3bf18&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-05-28 23:04:44 +0200'>2021-05-28</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=d7c356edb9719f1e236ee926c0288f914076481a'>gnu-maintenance: 'release-file?' accepts 'v' prefix as in "PKG-v1.2.tgz".</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/gnu-maintenance.scm (%tarball-rx, %package-name-rx): Accept 'v'
and 'V' prefixes.  Accept ".tgz" extension.
* tests/gnu-maintenance.scm ("release-file?"): Add test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-04-05 12:03:09 +0200'>2021-04-05</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=ceeea60bbc1e2be6a86cef208fcd80eb61c92934'>gnu-maintenance: Recognize more source tarball naming schemes.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/gnu-maintenance.scm (%package-name-rx): Add ".src" and ".orig"
suffixes.
* tests/gnu-maintenance.scm ("release-file?"): Add mpg321 and bvi
examples.
("tarball-&gt;version"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-03-29 23:33:40 +0200'>2021-03-29</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=1575da60628cf2594cd7b1ab0812ec4c50ac5092'>gnu-maintenance: Recognize "-source" tarball suffix.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/47398&gt;.
Reported by Léo Le Bouter &lt;lle-bout@zaclys.net&gt;.

* guix/gnu-maintenance.scm (%tarball-rx): Add "-[Ss]ource" suffix.
* tests/gnu-maintenance.scm ("release-file?"): Add exiv2 example.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-03-20 22:29:14 +0100'>2021-03-20</span></td><td><a href='/guix/commit/tests/gnu-maintenance.scm?id=1710e8cb59e2ef6f1e0eb19235b6a4f1b8158bc4'>gnu-maintenance: Accept underscores as package/version separators.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/47256&gt;.
Reported by Léo Le Bouter &lt;lle-bout@zaclys.net&gt;.

* guix/gnu-maintenance.scm (%tarball-rx, %package-name-rx): Accept
underscore as the package/version separator in tarball names.
* tests/gnu-maintenance.scm ("release-file?"): Add "mediainfo" test.
</span></span></td><td>Ludovic Courtès</td></tr>