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
@@ -617,7 +617,7 @@
         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));
@@ -719,15 +719,18 @@
             pdf_xml_tag_close(s, "rdf:Description");
             pdf_xml_newline(s);
 
-            pdf_xml_tag_open_beg(s, "rdf:Description");
-            pdf_xml_attribute_name(s, "rdf:about");
-            pdf_xml_attribute_value(s, instance_uuid);
-            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_attribute_name(s, "rdf:about");
+                pdf_xml_attribute_value(s, instance_uuid);
+                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_attribute_name(s, "rdf:about");
a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-07-13 10:49:40 -0400'>2022-07-13</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=dcf133587ac7d73ba306a314e1a496a7efb9960b'>tests: build-emacs-utils: Allow test to pass on Emacs 27 too.</a><span class='msg-avail'>...<span class='msg-tooltip'>* tests/build-emacs-utils.scm
("emacs-batch-script: raise &amp;emacs-batch-error on failure"): More loosely
match expected error string, which differs between Emacs 27 and Emacs 28.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-06-17 23:39:32 +0200'>2022-06-17</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=c3afbd05bf541b31b122e6093ff10eabf6a47926'>guix: emacs-utils: Add emacs-header-parse.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/emacs-utils.scm (emacs-header-parse): New procedure.

* tests/build-emacs-utils.scm ("emacs-header-parse: fetch version",
  "emacs-header-parse: fetch keywords", "emacs-header-parse: fetch
  nonexistent author"): New tests.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Fredrik Salomonsson</td></tr>
<tr><td><span title='2022-06-17 23:39:31 +0200'>2022-06-17</span></td><td><a href='/guix/commit/tests/build-emacs-utils.scm?id=f8275916fc6fcb3dd9bd8ef7dc4ddce2dca98c7d'>guix: emacs-utils: Add emacs-batch-script.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/build/emacs-utils.scm (emacs-batch-script): New procedure.

* tests/build-emacs-utils.scm: New file.

* Makefile.am (TESTS): Add `tests/build-emacs-utils.scm'.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Fredrik Salomonsson</td></tr>