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File msgfmt-remove-pot-creation-date.patch of Package gettext-runtime

commit d13f165b83701dffc14f7151419e0c00c00c0d1b
Author: John Darrington <john@darrington.wattle.id.au>
Date:   Thu Dec 15 21:56:44 2016 +0100

    msgfmt: Remove POT-Creation-Date field from the header in the output.
    
    This helps reproducible builds.
    Reported at <https://savannah.gnu.org/bugs/?49654>.
    * gettext-tools/src/msgl-header.h (message_list_delete_header_field): New
    declaration.
    * gettext-tools/src/msgl-header.c (known_fields): New variable, extracted from
    msgdomain_list_set_header_field.
    (message_list_delete_header_field): New function.
    * gettext-tools/src/write-mo.c: Include msgl-header.h.
    (msgdomain_write_mo): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-java.c: Include msgl-header.h.
    (msgdomain_write_java): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-csharp.c: Include msgl-header.h.
    (msgdomain_write_csharp): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-resources.c: Include msgl-header.h.
    (msgdomain_write_csharp_resources): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-tcl.c: Include msgl-header.h.
    (msgdomain_write_tcl): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-qt.c: Include msgl-header.h.
    (msgdomain_write_qt): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-desktop.c: Include msgl-header.h.
    (msgdomain_write_desktop): Delete the POT-Creation-Date field.
    * gettext-tools/src/write-xml.c: Include msgl-header.h.
    (msgdomain_write_xml): Delete the POT-Creation-Date field.
    * gettext-tools/tests/msgfmt-19: New file, based on
    gettext-tools/tests/msgfmt-18.
    * gettext-tools/tests/Makefile.am (TESTS): Add it.

diff --git a/gettext-tools/src/msgl-header.c b/gettext-tools/src/msgl-header.c
index 987c1c47e..25ae33af3 100644
--- a/gettext-tools/src/msgl-header.c
+++ b/gettext-tools/src/msgl-header.c
@@ -30,16 +30,12 @@
 #define SIZEOF(a) (sizeof(a) / sizeof(a[0]))
 
 
-void
-msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
-                                 const char *field, const char *value)
+/* The known fields in their usual order.  */
+static const struct
 {
-  /* The known fields in their usual order.  */
-  static const struct
-    {
-      const char *name;
-      size_t len;
-    }
+  const char *name;
+  size_t len;
+}
   known_fields[] =
     {
       { "Project-Id-Version:", sizeof ("Project-Id-Version:") - 1 },
@@ -54,6 +50,11 @@ msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
       { "Content-Transfer-Encoding:",
         sizeof ("Content-Transfer-Encoding:") - 1 }
     };
+
+void
+msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
+                                 const char *field, const char *value)
+{
   size_t field_len;
   int field_index;
   size_t k, i;
@@ -168,3 +169,71 @@ msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
           }
     }
 }
+
+
+void
+message_list_delete_header_field (message_list_ty *mlp,
+                                  const char *field)
+{
+  size_t j;
+  int field_index;
+  size_t k;
+
+  /* Search the field in known_fields[].  */
+  field_index = -1;
+  for (k = 0; k < SIZEOF (known_fields); k++)
+    if (strcmp (known_fields[k].name, field) == 0)
+      {
+        field_index = k;
+        break;
+      }
+
+  size_t field_len;
+  field_len = strlen (field);
+
+  /* Search the header entry.  */
+  for (j = 0; j < mlp->nitems; j++)
+    if (is_header (mlp->item[j]) && !mlp->item[j]->obsolete)
+      {
+        message_ty *mp = mlp->item[j];
+
+        /* Modify the header entry.  */
+        const char *header = mp->msgstr;
+        char *new_header =
+          XCALLOC (strlen (header) + 1,
+                    char);
+
+        /* Test whether the field already occurs in the header entry.  */
+        const char *h;
+
+        for (h = header; *h != '\0'; )
+          {
+            if (strncmp (h, field, field_len) == 0)
+              break;
+            h = strchr (h, '\n');
+            if (h == NULL)
+              break;
+            h++;
+          }
+        if (h != NULL && *h != '\0')
+          {
+            /* Replace the field.  */
+            char *p = new_header;
+            memcpy (p, header, h - header);
+            p += h - header;
+            h = strchr (h, '\n');
+            if (h != NULL)
+              {
+                h++;
+                stpcpy (p, h);
+              }
+          }
+        else
+          {
+            char *p = new_header;
+            p = stpcpy (p, header);
+          }
+        
+        mp->msgstr = new_header;
+      }
+}
diff --git a/gettext-tools/src/msgl-header.h b/gettext-tools/src/msgl-header.h
index 968515711..34726e7b0 100644
--- a/gettext-tools/src/msgl-header.h
+++ b/gettext-tools/src/msgl-header.h
@@ -34,6 +34,9 @@ extern void
        msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
                                         const char *field, const char *value);
 
+extern void
+       message_list_delete_header_field (message_list_ty *mlp, const char *field);
+
 
 #ifdef __cplusplus
 }
diff --git a/gettext-tools/src/write-csharp.c b/gettext-tools/src/write-csharp.c
index 5cf573a0f..30e8411cc 100644
--- a/gettext-tools/src/write-csharp.c
+++ b/gettext-tools/src/write-csharp.c
@@ -78,6 +78,7 @@
 #include "message.h"
 #include "msgfmt.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "plural-exp.h"
 #include "po-charset.h"
 #include "xalloc.h"
@@ -645,6 +646,8 @@ msgdomain_write_csharp (message_list_ty *mlp, const char *canon_encoding,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+  
   /* Create a temporary directory where we can put the C# file.
      A simple temporary file would also be possible but would require us to
      define our own variant of mkstemp(): On one hand the functions mktemp(),
diff --git a/gettext-tools/src/write-desktop.c b/gettext-tools/src/write-desktop.c
index 898ac3024..e568d47fb 100644
--- a/gettext-tools/src/write-desktop.c
+++ b/gettext-tools/src/write-desktop.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include "error.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "po-charset.h"
 #include "read-catalog.h"
 #include "read-po.h"
@@ -203,6 +204,8 @@ msgdomain_write_desktop (message_list_ty *mlp,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+  
   /* Create a single-element operands and run the bulk operation on it.  */
   operand.language = (char *) locale_name;
   operand.mlp = mlp;
diff --git a/gettext-tools/src/write-java.c b/gettext-tools/src/write-java.c
index eef8c79d2..039ed94d9 100644
--- a/gettext-tools/src/write-java.c
+++ b/gettext-tools/src/write-java.c
@@ -61,6 +61,7 @@
 #include "message.h"
 #include "msgfmt.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "plural-exp.h"
 #include "po-charset.h"
 #include "xalloc.h"
@@ -1066,6 +1067,8 @@ msgdomain_write_java (message_list_ty *mlp, const char *canon_encoding,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+
   if (output_source)
     {
       tmpdir = NULL;
diff --git a/gettext-tools/src/write-mo.c b/gettext-tools/src/write-mo.c
index b4a789494..b99dece02 100644
--- a/gettext-tools/src/write-mo.c
+++ b/gettext-tools/src/write-mo.c
@@ -48,6 +48,9 @@
 #include "binary-io.h"
 #include "fwriteerror.h"
 #include "gettext.h"
+#include "read-catalog.h"
+#include "read-stringtable.h"
+#include "msgl-header.h"
 
 #define _(str) gettext (str)
 
@@ -804,6 +807,7 @@ msgdomain_write_mo (message_list_ty *mlp,
 
       if (output_file != NULL)
         {
+          message_list_delete_header_field (mlp, "POT-Creation-Date:");
           write_table (output_file, mlp);
 
           /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-qt.c b/gettext-tools/src/write-qt.c
index 978bf0938..4a47d241f 100644
--- a/gettext-tools/src/write-qt.c
+++ b/gettext-tools/src/write-qt.c
@@ -35,6 +35,7 @@
 #include "message.h"
 #include "po-charset.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "hash-string.h"
 #include "unistr.h"
 #include "xalloc.h"
@@ -742,6 +743,7 @@ strings, not in the untranslated strings\n")));
 
       if (output_file != NULL)
         {
+          message_list_delete_header_field (mlp, "POT-Creation-Date:");
           write_qm (output_file, mlp);
 
           /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-resources.c b/gettext-tools/src/write-resources.c
index e5103c4b0..ec74eadcd 100644
--- a/gettext-tools/src/write-resources.c
+++ b/gettext-tools/src/write-resources.c
@@ -38,6 +38,7 @@
 #include "message.h"
 #include "msgfmt.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "po-charset.h"
 #include "xalloc.h"
 #include "concat-filename.h"
@@ -114,6 +115,8 @@ msgdomain_write_csharp_resources (message_list_ty *mlp,
                                   const char *domain_name,
                                   const char *file_name)
 {
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+  
   /* If no entry for this domain don't even create the file.  */
   if (mlp->nitems != 0)
     {
diff --git a/gettext-tools/src/write-tcl.c b/gettext-tools/src/write-tcl.c
index 0dbe3aa88..04b62d9c8 100644
--- a/gettext-tools/src/write-tcl.c
+++ b/gettext-tools/src/write-tcl.c
@@ -34,6 +34,7 @@
 #include "xerror.h"
 #include "message.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "po-charset.h"
 #include "xalloc.h"
 #include "xmalloca.h"
@@ -216,6 +217,7 @@ but the Tcl message catalog format doesn't support plural handling\n")));
         return 1;
       }
 
+    message_list_delete_header_field (mlp, "POT-Creation-Date:");
     write_msg (output_file, mlp, frobbed_locale_name);
 
     /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-xml.c b/gettext-tools/src/write-xml.c
index 79b7b5dbc..f6cd6c003 100644
--- a/gettext-tools/src/write-xml.c
+++ b/gettext-tools/src/write-xml.c
@@ -29,6 +29,7 @@
 #include <stdio.h>
 #include "error.h"
 #include "msgl-iconv.h"
+#include "msgl-header.h"
 #include "po-charset.h"
 #include "read-catalog.h"
 #include "read-po.h"
@@ -94,6 +95,8 @@ msgdomain_write_xml (message_list_ty *mlp,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+  
   /* Create a single-element operands and run the bulk operation on it.  */
   operand.language = (char *) locale_name;
   operand.mlp = mlp;
diff --git a/gettext-tools/tests/Makefile.am b/gettext-tools/tests/Makefile.am
index 0dfb4d867..38b47b922 100644
--- a/gettext-tools/tests/Makefile.am
+++ b/gettext-tools/tests/Makefile.am
@@ -46,7 +46,7 @@ TESTS = gettext-1 gettext-2 gettext-3 gettext-4 gettext-5 gettext-6 gettext-7 \
 	msgfilter-sr-latin-1 msgfilter-quote-1 \
 	msgfmt-1 msgfmt-2 msgfmt-3 msgfmt-4 msgfmt-5 msgfmt-6 msgfmt-7 \
 	msgfmt-8 msgfmt-9 msgfmt-10 msgfmt-11 msgfmt-12 msgfmt-13 msgfmt-14 \
-	msgfmt-15 msgfmt-16 msgfmt-17 msgfmt-18 \
+	msgfmt-15 msgfmt-16 msgfmt-17 msgfmt-18 msgfmt-19 \
 	msgfmt-properties-1 \
 	msgfmt-qt-1 msgfmt-qt-2 \
 	msgfmt-desktop-1 msgfmt-desktop-2 \
diff --git a/gettext-tools/tests/msgfmt-19 b/gettext-tools/tests/msgfmt-19
new file mode 100755
index 000000000..88574c817
--- /dev/null
+++ b/gettext-tools/tests/msgfmt-19
@@ -0,0 +1,66 @@
+#! /bin/sh
+. "${srcdir=.}/init.sh"; path_prepend_ . ../src
+
+# Test accelerators.
+
+cat <<\EOF > mf-19-1.po
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR Free Software Foundation, Inc.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: GNU bison\n"
+"POT-Creation-Date: 2017-04-05 19:47+0200\n"
+"PO-Revision-Date: 2017-06-07 09:07+0000\n"
+"Last-Translator: ABC DEF <abc@gnu.uucp>\n"
+"Language-Team: test <test@li.org>\n"
+"Language: test\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+msgid "pen &File"
+msgstr "pen File"
+
+msgid "how _Help"
+msgstr "how Help"
+EOF
+
+
+cat <<\EOF > mf-19-2.po
+# SOME DESCRIPTIVE TITLE.
+# Copyright (C) YEAR Free Software Foundation, Inc.
+# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
+#
+msgid ""
+msgstr ""
+"Project-Id-Version: GNU bison\n"
+"POT-Creation-Date: 2016-03-04 18:46+0100\n"
+"PO-Revision-Date: 2017-06-07 09:07+0000\n"
+"Last-Translator: ABC DEF <abc@gnu.uucp>\n"
+"Language-Team: test <test@li.org>\n"
+"Language: test\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+
+msgid "pen &File"
+msgstr "pen File"
+
+msgid "how _Help"
+msgstr "how Help"
+EOF
+
+
+: ${MSGFMT=msgfmt}
+${MSGFMT} -o mf-19-1.mo mf-19-1.po 2>/dev/null
+test $? = 0 || { Exit 1; }
+
+: ${MSGFMT=msgfmt}
+${MSGFMT} -o mf-19-2.mo mf-19-2.po 2>/dev/null
+test $? = 0 || { Exit 1; }
+
+: ${DIFF=diff}
+${DIFF} mf-19-1.mo mf-19-2.mo
+test $? = 0 || { Exit 1; }
commit dea676293993e16ae50119ce1edfcc18e586c3f7
Author: Bruno Haible <bruno@clisp.org>
Date:   Thu Dec 15 22:51:00 2016 +0100

    Polish the last commit.

diff --git a/gettext-tools/src/msgl-header.c b/gettext-tools/src/msgl-header.c
index 25ae33af3..219b412ab 100644
--- a/gettext-tools/src/msgl-header.c
+++ b/gettext-tools/src/msgl-header.c
@@ -36,20 +36,20 @@ static const struct
   const char *name;
   size_t len;
 }
-  known_fields[] =
-    {
-      { "Project-Id-Version:", sizeof ("Project-Id-Version:") - 1 },
-      { "Report-Msgid-Bugs-To:", sizeof ("Report-Msgid-Bugs-To:") - 1 },
-      { "POT-Creation-Date:", sizeof ("POT-Creation-Date:") - 1 },
-      { "PO-Revision-Date:", sizeof ("PO-Revision-Date:") - 1 },
-      { "Last-Translator:", sizeof ("Last-Translator:") - 1 },
-      { "Language-Team:", sizeof ("Language-Team:") - 1 },
-      { "Language:", sizeof ("Language:") - 1 },
-      { "MIME-Version:", sizeof ("MIME-Version:") - 1 },
-      { "Content-Type:", sizeof ("Content-Type:") - 1 },
-      { "Content-Transfer-Encoding:",
-        sizeof ("Content-Transfer-Encoding:") - 1 }
-    };
+known_fields[] =
+  {
+    { "Project-Id-Version:", sizeof ("Project-Id-Version:") - 1 },
+    { "Report-Msgid-Bugs-To:", sizeof ("Report-Msgid-Bugs-To:") - 1 },
+    { "POT-Creation-Date:", sizeof ("POT-Creation-Date:") - 1 },
+    { "PO-Revision-Date:", sizeof ("PO-Revision-Date:") - 1 },
+    { "Last-Translator:", sizeof ("Last-Translator:") - 1 },
+    { "Language-Team:", sizeof ("Language-Team:") - 1 },
+    { "Language:", sizeof ("Language:") - 1 },
+    { "MIME-Version:", sizeof ("MIME-Version:") - 1 },
+    { "Content-Type:", sizeof ("Content-Type:") - 1 },
+    { "Content-Transfer-Encoding:", sizeof ("Content-Transfer-Encoding:") - 1 }
+  };
+
 
 void
 msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
@@ -175,21 +175,8 @@ void
 message_list_delete_header_field (message_list_ty *mlp,
                                   const char *field)
 {
+  size_t field_len = strlen (field);
   size_t j;
-  int field_index;
-  size_t k;
-
-  /* Search the field in known_fields[].  */
-  field_index = -1;
-  for (k = 0; k < SIZEOF (known_fields); k++)
-    if (strcmp (known_fields[k].name, field) == 0)
-      {
-        field_index = k;
-        break;
-      }
-
-  size_t field_len;
-  field_len = strlen (field);
 
   /* Search the header entry.  */
   for (j = 0; j < mlp->nitems; j++)
@@ -199,11 +186,8 @@ message_list_delete_header_field (message_list_ty *mlp,
 
         /* Modify the header entry.  */
         const char *header = mp->msgstr;
-        char *new_header =
-          XCALLOC (strlen (header) + 1,
-                    char);
 
-        /* Test whether the field already occurs in the header entry.  */
+        /* Test whether the field occurs in the header entry.  */
         const char *h;
 
         for (h = header; *h != '\0'; )
@@ -217,7 +201,9 @@ message_list_delete_header_field (message_list_ty *mlp,
           }
         if (h != NULL && *h != '\0')
           {
-            /* Replace the field.  */
+            /* Delete the field.  */
+            char *new_header = XCALLOC (strlen (header) + 1, char);
+
             char *p = new_header;
             memcpy (p, header, h - header);
             p += h - header;
@@ -225,15 +211,12 @@ message_list_delete_header_field (message_list_ty *mlp,
             if (h != NULL)
               {
                 h++;
-                stpcpy (p, h);
+                strcpy (p, h);
               }
+            else
+              *p = '\0';
+
+            mp->msgstr = new_header;
           }
-        else
-          {
-            char *p = new_header;
-            p = stpcpy (p, header);
-          }
-        
-        mp->msgstr = new_header;
       }
 }
diff --git a/gettext-tools/src/msgl-header.h b/gettext-tools/src/msgl-header.h
index 34726e7b0..35524a37f 100644
--- a/gettext-tools/src/msgl-header.h
+++ b/gettext-tools/src/msgl-header.h
@@ -34,8 +34,11 @@ extern void
        msgdomain_list_set_header_field (msgdomain_list_ty *mdlp,
                                         const char *field, const char *value);
 
+/* Remove the given field from the header.
+   The FIELD name ends in a colon.  */
 extern void
-       message_list_delete_header_field (message_list_ty *mlp, const char *field);
+       message_list_delete_header_field (message_list_ty *mlp,
+                                         const char *field);
 
 
 #ifdef __cplusplus
diff --git a/gettext-tools/src/write-csharp.c b/gettext-tools/src/write-csharp.c
index 30e8411cc..161cd4f45 100644
--- a/gettext-tools/src/write-csharp.c
+++ b/gettext-tools/src/write-csharp.c
@@ -646,8 +646,10 @@ msgdomain_write_csharp (message_list_ty *mlp, const char *canon_encoding,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  /* Support for "reproducible builds": Delete information that may vary
+     between builds in the same conditions.  */
   message_list_delete_header_field (mlp, "POT-Creation-Date:");
-  
+
   /* Create a temporary directory where we can put the C# file.
      A simple temporary file would also be possible but would require us to
      define our own variant of mkstemp(): On one hand the functions mktemp(),
diff --git a/gettext-tools/src/write-desktop.c b/gettext-tools/src/write-desktop.c
index e568d47fb..657620dcb 100644
--- a/gettext-tools/src/write-desktop.c
+++ b/gettext-tools/src/write-desktop.c
@@ -204,8 +204,10 @@ msgdomain_write_desktop (message_list_ty *mlp,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  /* Support for "reproducible builds": Delete information that may vary
+     between builds in the same conditions.  */
   message_list_delete_header_field (mlp, "POT-Creation-Date:");
-  
+
   /* Create a single-element operands and run the bulk operation on it.  */
   operand.language = (char *) locale_name;
   operand.mlp = mlp;
diff --git a/gettext-tools/src/write-java.c b/gettext-tools/src/write-java.c
index 039ed94d9..9ddfac868 100644
--- a/gettext-tools/src/write-java.c
+++ b/gettext-tools/src/write-java.c
@@ -1067,6 +1067,8 @@ msgdomain_write_java (message_list_ty *mlp, const char *canon_encoding,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  /* Support for "reproducible builds": Delete information that may vary
+     between builds in the same conditions.  */
   message_list_delete_header_field (mlp, "POT-Creation-Date:");
 
   if (output_source)
diff --git a/gettext-tools/src/write-mo.c b/gettext-tools/src/write-mo.c
index b99dece02..69196550c 100644
--- a/gettext-tools/src/write-mo.c
+++ b/gettext-tools/src/write-mo.c
@@ -45,12 +45,10 @@
 #include "xsize.h"
 #include "xalloc.h"
 #include "xmalloca.h"
+#include "msgl-header.h"
 #include "binary-io.h"
 #include "fwriteerror.h"
 #include "gettext.h"
-#include "read-catalog.h"
-#include "read-stringtable.h"
-#include "msgl-header.h"
 
 #define _(str) gettext (str)
 
@@ -789,6 +787,10 @@ msgdomain_write_mo (message_list_ty *mlp,
   /* If no entry for this domain don't even create the file.  */
   if (mlp->nitems != 0)
     {
+      /* Support for "reproducible builds": Delete information that may vary
+         between builds in the same conditions.  */
+      message_list_delete_header_field (mlp, "POT-Creation-Date:");
+
       if (strcmp (domain_name, "-") == 0)
         {
           output_file = stdout;
@@ -807,7 +809,6 @@ msgdomain_write_mo (message_list_ty *mlp,
 
       if (output_file != NULL)
         {
-          message_list_delete_header_field (mlp, "POT-Creation-Date:");
           write_table (output_file, mlp);
 
           /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-qt.c b/gettext-tools/src/write-qt.c
index 4a47d241f..b3cca5a8e 100644
--- a/gettext-tools/src/write-qt.c
+++ b/gettext-tools/src/write-qt.c
@@ -725,6 +725,10 @@ strings, not in the untranslated strings\n")));
           }
       }
 
+      /* Support for "reproducible builds": Delete information that may vary
+         between builds in the same conditions.  */
+      message_list_delete_header_field (mlp, "POT-Creation-Date:");
+
       if (strcmp (domain_name, "-") == 0)
         {
           output_file = stdout;
@@ -743,7 +747,6 @@ strings, not in the untranslated strings\n")));
 
       if (output_file != NULL)
         {
-          message_list_delete_header_field (mlp, "POT-Creation-Date:");
           write_qm (output_file, mlp);
 
           /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-resources.c b/gettext-tools/src/write-resources.c
index ec74eadcd..8cc33cc13 100644
--- a/gettext-tools/src/write-resources.c
+++ b/gettext-tools/src/write-resources.c
@@ -115,8 +115,6 @@ msgdomain_write_csharp_resources (message_list_ty *mlp,
                                   const char *domain_name,
                                   const char *file_name)
 {
-  message_list_delete_header_field (mlp, "POT-Creation-Date:");
-  
   /* If no entry for this domain don't even create the file.  */
   if (mlp->nitems != 0)
     {
@@ -161,6 +159,10 @@ but the C# .resources format doesn't support plural handling\n")));
       /* Convert the messages to Unicode.  */
       iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+      /* Support for "reproducible builds": Delete information that may vary
+         between builds in the same conditions.  */
+      message_list_delete_header_field (mlp, "POT-Creation-Date:");
+
       /* Execute the WriteResource program.  */
       {
         const char *args[2];
diff --git a/gettext-tools/src/write-tcl.c b/gettext-tools/src/write-tcl.c
index 04b62d9c8..b61608e76 100644
--- a/gettext-tools/src/write-tcl.c
+++ b/gettext-tools/src/write-tcl.c
@@ -185,6 +185,10 @@ but the Tcl message catalog format doesn't support plural handling\n")));
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  /* Support for "reproducible builds": Delete information that may vary
+     between builds in the same conditions.  */
+  message_list_delete_header_field (mlp, "POT-Creation-Date:");
+
   /* Now create the file.  */
   {
     size_t len;
@@ -217,7 +221,6 @@ but the Tcl message catalog format doesn't support plural handling\n")));
         return 1;
       }
 
-    message_list_delete_header_field (mlp, "POT-Creation-Date:");
     write_msg (output_file, mlp, frobbed_locale_name);
 
     /* Make sure nothing went wrong.  */
diff --git a/gettext-tools/src/write-xml.c b/gettext-tools/src/write-xml.c
index f6cd6c003..5c719f92e 100644
--- a/gettext-tools/src/write-xml.c
+++ b/gettext-tools/src/write-xml.c
@@ -95,8 +95,10 @@ msgdomain_write_xml (message_list_ty *mlp,
   /* Convert the messages to Unicode.  */
   iconv_message_list (mlp, canon_encoding, po_charset_utf8, NULL);
 
+  /* Support for "reproducible builds": Delete information that may vary
+     between builds in the same conditions.  */
   message_list_delete_header_field (mlp, "POT-Creation-Date:");
-  
+
   /* Create a single-element operands and run the bulk operation on it.  */
   operand.language = (char *) locale_name;
   operand.mlp = mlp;
diff --git a/gettext-tools/tests/msgfmt-19 b/gettext-tools/tests/msgfmt-19
index 88574c817..76d4a739d 100755
--- a/gettext-tools/tests/msgfmt-19
+++ b/gettext-tools/tests/msgfmt-19
@@ -1,7 +1,8 @@
 #! /bin/sh
 . "${srcdir=.}/init.sh"; path_prepend_ . ../src
 
-# Test accelerators.
+# Test that PO files that differ only in the POT-Creation-Date yield the
+# exact same .mo file.
 
 cat <<\EOF > mf-19-1.po
 # SOME DESCRIPTIVE TITLE.
@@ -20,14 +21,13 @@ msgstr ""
 "Content-Type: text/plain; charset=UTF-8\n"
 "Content-Transfer-Encoding: 8bit\n"
 
-msgid "pen &File"
-msgstr "pen File"
+msgid "Open &File"
+msgstr "Open File"
 
-msgid "how _Help"
-msgstr "how Help"
+msgid "Show _Help"
+msgstr "Show Help"
 EOF
 
-
 cat <<\EOF > mf-19-2.po
 # SOME DESCRIPTIVE TITLE.
 # Copyright (C) YEAR Free Software Foundation, Inc.
@@ -45,14 +45,13 @@ msgstr ""
 "Content-Type: text/plain; charset=UTF-8\n"
 "Content-Transfer-Encoding: 8bit\n"
 
-msgid "pen &File"
-msgstr "pen File"
+msgid "Open &File"
+msgstr "Open File"
 
-msgid "how _Help"
-msgstr "how Help"
+msgid "Show _Help"
+msgstr "Show Help"
 EOF
 
-
 : ${MSGFMT=msgfmt}
 ${MSGFMT} -o mf-19-1.mo mf-19-1.po 2>/dev/null
 test $? = 0 || { Exit 1; }