Improve maintainability by rewriting the mkheader helper.

* src/mkheader.c: New.  Based on the mkheader from Libassuan.
* src/mkheader.awk: Remove.
* src/errnos.in: Add trailing linefeed.
* src/gpg-error.h.in: Change meta include directives for use with
mkheader.c.
* src/Makefile.am (EXTRA_DIST): Replace mkheader.awk by mkheader.c
(BUILT_SOURCES): Remove extra-h.in.
(CLEANFILES): Remove extra-h.in.  Add mkheader.c.
(parts_of_gpg_error_h): New.
(extra-h.in): Remove rule.
(mkheader): Add rule.
(gpg-error.h): Change rule to use mkheader.

Signed-off-by: Werner Koch <[email protected]>

5 files changed, 404 insertions, 261 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 7143dbd..74d89be 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,5 +1,5 @@
 # Makefile.am for libgpg-error.
-# Copyright (C) 2003, 2004 g10 Code GmbH
+# Copyright (C) 2003, 2004, 2014 g10 Code GmbH
 #
 # This file is part of libgpg-error.
 #
@@ -14,8 +14,7 @@
 # GNU Lesser General Public License for more details.
 #
 # You should have received a copy of the GNU Lesser General Public
-# License along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+# License along with this program; if not, see <http://www.gnu.org/licenses/>.
 
 # We distribute the generated sources err-sources.h and err-codes.h,
 # because they are needed to build the po directory, and they don't
@@ -41,20 +40,20 @@ m4data_DATA = gpg-error.m4
 EXTRA_DIST = mkstrtable.awk err-sources.h.in err-codes.h.in \
 	mkerrnos.awk errnos.in README \
 	mkerrcodes.awk mkerrcodes1.awk mkerrcodes2.awk mkerrcodes.c \
-	mkheader.awk gpg-error.h.in mkw32errmap.c w32-add.h w32ce-add.h \
+	mkheader.c gpg-error.h.in mkw32errmap.c w32-add.h w32ce-add.h \
 	err-sources.h err-codes.h gpg-error-config.in gpg-error.m4 \
 	gpg-error.def.in versioninfo.rc.in
 
 BUILT_SOURCES = err-sources.h err-codes.h code-to-errno.h code-from-errno.h \
 	err-sources-sym.h err-codes-sym.h errnos-sym.h gpg-error.h \
-	gpg-error.def extra-h.in mkw32errmap.map.c
+	gpg-error.def mkw32errmap.map.c
 
 tmp_files = _mkerrcodes.h _gpg-error.def.h mkw32errmap.tab.h mkw32errmap.map.c
 
 CLEANFILES = err-sources.h err-codes.h code-to-errno.h code-from-errno.h \
 	gpg-error.h mkerrcodes mkerrcodes.h gpg-error.def mkw32errmap.tab.h \
 	mkw32errmap.map.c err-sources-sym.h err-codes-sym.h errnos-sym.h \
-	gpg-extra/errno.h extra-h.in $(tmp_files)
+	gpg-extra/errno.h mkheader $(tmp_files)
 
 if HAVE_W32_SYSTEM
 arch_sources = w32-gettext.c
@@ -99,6 +98,15 @@ libgpg_error_la_LDFLAGS = -version-info \
   @LIBGPG_ERROR_LT_CURRENT@:@LIBGPG_ERROR_LT_REVISION@:@LIBGPG_ERROR_LT_AGE@ \
   $(no_undefined) $(export_symbols)
 
+parts_of_gpg_error_h = 	 \
+	gpg-error.h.in   \
+	err-sources.h.in \
+	err-codes.h.in 	 \
+	errnos.in 	 \
+	w32-add.h	 \
+	w32ce-add.h
+
+
 libgpg_error_la_SOURCES = gpg-error.h gettext.h $(arch_sources) \
 	init.c init.h version.c \
 	strsource.c strerror.c code-to-errno.c code-from-errno.c
@@ -187,32 +195,14 @@ errnos-sym.h: Makefile mkstrtable.awk errnos.in
 		-v prefix=GPG_ERR_ -v namespace=errnos_ \
 		$(srcdir)/errnos.in >$@
 
-# We depend on versioninfo.rc because that is build by config.status
-# and thus has up-to-date version numbers.
-extra-h.in: Makefile w32-add.h w32ce-add.h versioninfo.rc
-	-rm extra-h.in
-	echo "/* The version string of this header. */" >>extra-h.in
-	echo "#define GPG_ERROR_VERSION \"$(PACKAGE_VERSION)\"" >>extra-h.in
-	echo >>extra-h.in
-	echo "/* The version number of this header. */" >>extra-h.in
-	echo "#define GPG_ERROR_VERSION_NUMBER $(VERSION_NUMBER)" >>extra-h.in
-	echo >>extra-h.in
-if HAVE_W32_SYSTEM
-	cat $(srcdir)/w32-add.h >>extra-h.in
-endif
-if HAVE_W32CE_SYSTEM
-	cat $(srcdir)/w32ce-add.h >>extra-h.in
-endif
-	echo EOF >>extra-h.in
-
-gpg-error.h: Makefile mkheader.awk err-sources.h.in err-codes.h.in \
-	    	 errnos.in extra-h.in gpg-error.h.in
-	$(AWK) -f $(srcdir)/mkheader.awk \
-		$(srcdir)/err-sources.h.in \
-		$(srcdir)/err-codes.h.in \
-		$(srcdir)/errnos.in \
-		extra-h.in \
-		$(srcdir)/gpg-error.h.in > $@
+mkheader: mkheader.c Makefile
+	$(CC_FOR_BUILD) -g -O0 -I. -I$(srcdir) -o $@ $(srcdir)/mkheader.c
+
+# We also depend on versioninfo.rc because that is build by
+# config.status and thus has up-to-date version numbers.
+gpg-error.h: Makefile mkheader $(parts_of_gpg_error_h) versioninfo.rc
+	./mkheader $(host_os) $(srcdir)/gpg-error.h.in \
+                   $(PACKAGE_VERSION) $(VERSION_NUMBER) >$@
 
 
 install-data-local:
diff --git a/src/errnos.in b/src/errnos.in
index 0688047..018fb9a 100644
--- a/src/errnos.in
+++ b/src/errnos.in
@@ -1,5 +1,5 @@
-# errnos.h.in - List of system error values input file.
-/* errnos.h - List of system error values.
+# errnos.in - List of system error values input file.
+/* errnos.in - List of system error values.
    Copyright (C) 2003, 2004 g10 Code GmbH
 
    This file is part of libgpg-error.
@@ -8,12 +8,12 @@
    modify it under the terms of the GNU Lesser General Public License
    as published by the Free Software Foundation; either version 2.1 of
    the License, or (at your option) any later version.
- 
+
    libgpg-error is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
- 
+
    You should have received a copy of the GNU Lesser General Public
    License along with libgpg-error; if not, write to the Free
    Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
@@ -169,4 +169,4 @@
 137	EUSERS
 138	EWOULDBLOCK
 139	EXDEV
-140	EXFULL
\ No newline at end of file
+140	EXFULL
diff --git a/src/gpg-error.h.in b/src/gpg-error.h.in
index 303fac0..a2fb044 100644
--- a/src/gpg-error.h.in
+++ b/src/gpg-error.h.in
@@ -1,5 +1,5 @@
-/* gpg-error.h - Public interface to libgpg-error.
-   Copyright (C) 2003, 2004, 2010, 2013 g10 Code GmbH
+/* gpg-error.h - Public interface to libgpg-error.               -*- c -*-
+   Copyright (C) 2003, 2004, 2010, 2013, 2014 g10 Code GmbH
 
    This file is part of libgpg-error.
 
@@ -15,6 +15,8 @@
 
    You should have received a copy of the GNU Lesser General Public
    License along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+   @configure_input@
  */
 
 
@@ -77,7 +79,7 @@ extern "C" {
    entries.  */
 typedef enum
   {
-@include err-sources.h.in
+@include:err-sources@
 
     /* This is one more than the largest allowed entry.  */
     GPG_ERR_SOURCE_DIM = 128
@@ -90,11 +92,11 @@ typedef enum
    entries.  */
 typedef enum
   {
-@include err-codes.h.in
+@include:err-codes@
 
     /* The following error codes are used to map system errors.  */
 #define GPG_ERR_SYSTEM_ERROR	(1 << 15)
-@include errnos.in
+@include:errnos@
 
     /* This is one more than the largest allowed entry.  */
     GPG_ERR_CODE_DIM = 65536
@@ -248,7 +250,13 @@ void gpg_err_set_errno (int err);
 /* Return or check the version.  */
 const char *gpg_error_check_version (const char *req_version);
 
-@include extra-h.in
+/* The version string of this header. */
+#define GPG_ERROR_VERSION @version@
+
+/* The version number of this header. */
+#define GPG_ERROR_VERSION_NUMBER @version-number@
+
+@include:os-add@
 
 /* Self-documenting convenience functions.  */
 
diff --git a/src/mkheader.awk b/src/mkheader.awk
deleted file mode 100644
index 0ff08f9..0000000
--- a/src/mkheader.awk
+++ /dev/null
@@ -1,218 +0,0 @@
-# mkheader.awk
-# Copyright (C) 2003, 2004 g10 Code GmbH
-# 
-# This program is free software; you can redistribute it and/or
-# modify it under the terms of the GNU General Public License as
-# published by the Free Software Foundation; either version 2 of
-# the License, or (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-# General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
-#
-# As a special exception, g10 Code GmbH gives unlimited permission to
-# copy, distribute and modify the C source files that are the output
-# of mkheader.awk.  You need not follow the terms of the GNU General
-# Public License when using or distributing such scripts, even though
-# portions of the text of mkheader.awk appear in them.  The GNU
-# General Public License (GPL) does govern all other use of the material
-# that constitutes the mkheader.awk program.
-#
-# Certain portions of the mkheader.awk source text are designed to be
-# copied (in certain cases, depending on the input) into the output of
-# mkheader.awk.  We call these the "data" portions.  The rest of the
-# mkheader.awk source text consists of comments plus executable code
-# that decides which of the data portions to output in any given case.
-# We call these comments and executable code the "non-data" portions.
-# mkheader.h never copies any of the non-data portions into its output.
-#
-# This special exception to the GPL applies to versions of mkheader.awk
-# released by g10 Code GmbH.  When you make and distribute a modified version
-# of mkheader.awk, you may extend this special exception to the GPL to
-# apply to your modified version as well, *unless* your modified version
-# has the potential to copy into its output some of the text that was the
-# non-data portion of the version that you started with.  (In other words,
-# unless your change moves or copies text from the non-data portions to the
-# data portions.)  If your modification has such potential, you must delete
-# any notice of this special exception to the GPL from your modified version.
-
-# This script processes gpg-error.h.in in an awful way.
-# Its input is, one after another, the content of the err-sources.h.in file,
-# the err-codes.h.in file, the errnos.in file, and then gpg-error.h.in.
-# There is nothing fancy about this.
-#
-# An alternative would be to use getline to get the content of the first three files,
-# but then we need to pre-process gpg-error.h.in with configure to get
-# at the full path of the files in @srcdir@.
-
-BEGIN {
-  FS = "[\t]+";
-# sources_nr holds the number of error sources.
-  sources_nr = 0;
-# codes_nr holds the number of error codes.
-  codes_nr = 0;
-# errnos_nr holds the number of system errors.
-  errnos_nr = 0;
-# extra_nr holds the number of extra lines to be included.
-  extra_nr = 0
-
-# These variables walk us through our input.
-  sources_header = 1;
-  sources_body = 0;
-  between_sources_and_codes = 0;
-  codes_body = 0;
-  between_codes_and_errnos = 0;
-  errnos_body = 0;
-  extra_body = 0;
-  gpg_error_h = 0;
-
-  print "/* Output of mkheader.awk.  DO NOT EDIT.  -*- buffer-read-only: t -*- */";
-  print "";
-
-}
-
-
-sources_header {
-  if ($1 ~ /^[0123456789]+$/)
-    {
-      sources_header = 0;
-      sources_body = 1;
-    }      
-}
-
-sources_body {
-  sub (/\#.+/, "");
-  sub (/[ 	]+$/, ""); # Strip trailing space and tab characters.
-
-  if (/^$/)
-    next;
-
-  if ($1 == "")
-    {
-      sources_body = 0;
-      between_sources_and_codes = 1;
-    }
-  else
-    {
-# Remember the error source number and symbol of each error source.
-      sources_idx[sources_nr] = $1;
-      sources_sym[sources_nr] = $2;
-      sources_nr++;
-    }
-}
-
-between_sources_and_codes {
-  if ($1 ~ /^[0123456789]+$/)
-    {
-      between_sources_and_codes = 0;
-      codes_body = 1;
-    }      
-}
-
-codes_body {
-  sub (/\#.+/, "");
-  sub (/[ 	]+$/, ""); # Strip trailing space and tab characters.
-
-  if (/^$/)
-    next;
-
-  if ($1 == "")
-    {
-      codes_body = 0;
-      between_codes_and_errnos = 1;
-    }
-  else
-    {
-# Remember the error code number and symbol of each error source.
-      codes_idx[codes_nr] = $1;
-      codes_sym[codes_nr] = $2;
-      codes_nr++;
-    }
-}
-
-between_codes_and_errnos {
-  if ($1 ~ /^[0-9]/)
-    {
-      between_codes_and_errnos = 0;
-      errnos_body = 1;
-    }
-}
-
-errnos_body {
-  sub (/\#.+/, "");
-  sub (/[ 	]+$/, ""); # Strip trailing space and tab characters.
-
-  if (/^$/)
-    next;
-
-  if ($1 !~ /^[0-9]/)
-    {
-# Note that this assumes that extra_body.in doesn't start with a digit.
-      errnos_body = 0;
-      extra_body = 1;
-    }
-  else
-    {
-      errnos_idx[errnos_nr] = "GPG_ERR_SYSTEM_ERROR | " $1;
-      errnos_sym[errnos_nr] = "GPG_ERR_" $2;
-      errnos_nr++;
-    }
-}
-
-extra_body {
-  if (/^##/)
-    next
-
-  if (/^EOF/)
-    {
-      extra_body = 0;
-      gpg_error_h = 1;
-      next;
-    }
-  else
-    {
-      extra_line[extra_nr] = $0;
-      extra_nr++;
-    }
-}
-
-gpg_error_h {
-  if ($0 ~ /^@include err-sources/)
-    {
-      for (i = 0; i < sources_nr; i++)
-	{
-	  print "    " sources_sym[i] " = " sources_idx[i] ",";
-#	  print "#define " sources_sym[i] " (" sources_idx[i] ")";
-	}
-    }
-  else if ($0 ~ /^@include err-codes/)
-    {
-      for (i = 0; i < codes_nr; i++)
-	{
-	  print "    " codes_sym[i] " = " codes_idx[i] ",";
-#	  print "#define " codes_sym[i] " (" codes_idx[i] ")";
-	}
-    }
-  else if ($0 ~ /^@include errnos/)
-    {
-      for (i = 0; i < errnos_nr; i++)
-       {
-         print "    " errnos_sym[i] " = " errnos_idx[i] ",";
-#        print "#define " errnos_sym[i] " (" errnos_idx[i] ")";
-       }
-    }
-  else if ($0 ~ /^@include extra-h.in/)
-    {
-      for (i = 0; i < extra_nr; i++)
-	{
-            print extra_line[i];
-	}
-    }
-  else
-    print;
-}
diff --git a/src/mkheader.c b/src/mkheader.c
new file mode 100644
index 0000000..eea7914
--- /dev/null
+++ b/src/mkheader.c
@@ -0,0 +1,363 @@
+/* mkheader.c - Create a header file for libgpg-error
+ * Copyright (C) 2010 Free Software Foundation, Inc.
+ * Copyright (C) 2014 g10 Code GmbH
+ *
+ * This file is free software; as a special exception the author gives
+ * unlimited permission to copy and/or distribute it, with or without
+ * modifications, as long as this notice is preserved.
+ *
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#define PGM "mkheader"
+
+#define LINESIZE 1024
+
+static const char *host_os;
+static char *srcdir;
+static const char *hdr_version;
+static const char *hdr_version_number;
+
+
+/* Write LINE to stdout.  The function is allowed to modify LINE.  */
+static void
+write_str (char *line)
+{
+  if (fputs (line, stdout) == EOF)
+    {
+      fprintf (stderr, PGM ": error writing to stdout: %s\n", strerror (errno));
+      exit (1);
+    }
+}
+
+static void
+write_line (char *line)
+{
+  if (puts (line) == EOF)
+    {
+      fprintf (stderr, PGM ": error writing to stdout: %s\n", strerror (errno));
+      exit (1);
+    }
+}
+
+
+/* Write SOURCE or CODES line to stdout.  The function is allowed to
+   modify LINE.  Trailing white space is already removed.  Passing
+   NULL resets the internal state.  */
+static void
+write_sources_or_codes (char *line)
+{
+  static int in_intro;
+  char *p1, *p2;
+
+  if (!line)
+    {
+      in_intro = 1;
+      return;
+    }
+
+  if (!*line)
+    return;
+
+  if (in_intro)
+    {
+      if (!strchr ("0123456789", *line))
+        return;
+      in_intro = 0;
+    }
+
+  p1 = strtok (line, " \t");
+  p2 = p1? strtok (NULL, " \t") : NULL;
+
+  if (p1 && p2 && strchr ("0123456789", *p1) && *p2)
+    {
+      write_str ("    ");
+      write_str (p2);
+      write_str (" = ");
+      write_str (p1);
+      write_str (",\n");
+    }
+}
+
+
+/* Write system errnos to stdout.  The function is allowed to
+   modify LINE.  Trailing white space is already removed.  Passing
+   NULL resets the internal state.  */
+static void
+write_errnos_in (char *line)
+{
+  static int state;
+  char *p1, *p2;
+
+  if (!line)
+    {
+      state = 0;
+      return;
+    }
+
+  if (!*line)
+    return;
+
+  if (!state && strchr ("0123456789", *line))
+    state = 1;
+  else if (state == 1 && !strchr ("0123456789", *line))
+    state = 2;
+
+  if (state != 1)
+    return;
+
+  p1 = strtok (line, " \t");
+  p2 = p1? strtok (NULL, " \t") : NULL;
+
+  if (p1 && p2 && strchr ("0123456789", *p1) && *p2)
+    {
+      write_str ("    GPG_ERR_");
+      write_str (p2);
+      write_str (" = GPG_ERR_SYSTEM_ERROR | ");
+      write_str (p1);
+      write_str (",\n");
+    }
+}
+
+
+/* Include the file NAME from the source directory.  The included file
+   is not further expanded.  It may have comments indicated by a
+   double hash mark at the begin of a line.  OUTF is called for each
+   read line and passed a buffer with the content of line sans line
+   line endings. */
+static void
+include_file (const char *fname, int lnr, const char *name, void (*outf)(char*))
+{
+  FILE *fp;
+  char *incfname;
+  int inclnr;
+  char line[LINESIZE];
+
+  incfname = malloc (strlen (srcdir) + strlen (name) + 1);
+  if (!incfname)
+    {
+      fputs (PGM ": out of core\n", stderr);
+      exit (1);
+    }
+  strcpy (incfname, srcdir);
+  strcat (incfname, name);
+
+  fp = fopen (incfname, "r");
+  if (!fp)
+    {
+      fprintf (stderr, "%s:%d: error including `%s': %s\n",
+               fname, lnr, incfname, strerror (errno));
+      exit (1);
+    }
+
+  inclnr = 0;
+  while (fgets (line, LINESIZE, fp))
+    {
+      size_t n = strlen (line);
+
+      inclnr++;
+      if (!n || line[n-1] != '\n')
+        {
+          fprintf (stderr,
+                   "%s:%d: trailing linefeed missing, line too long or "
+                   "embedded nul character\n", incfname, inclnr);
+          fprintf (stderr,"%s:%d: note: file '%s' included from here\n",
+                   fname, lnr, incfname);
+          exit (1);
+        }
+      line[--n] = 0;
+      while (line[n] == ' ' || line[n] == '\t' || line[n] == '\r')
+        {
+          line[n] = 0;
+          if (!n)
+            break;
+          n--;
+        }
+
+      if (line[0] == '#' && line[1] == '#')
+        {
+          if (!strncmp (line+2, "EOF##", 5))
+            break; /* Forced EOF.  */
+        }
+      else
+        outf (line);
+    }
+  if (ferror (fp))
+    {
+      fprintf (stderr, "%s:%d: error reading `%s': %s\n",
+               fname, lnr, incfname, strerror (errno));
+      exit (1);
+    }
+  fclose (fp);
+  free (incfname);
+}
+
+
+static int
+write_special (const char *fname, int lnr, const char *tag)
+{
+  if (!strcmp (tag, "version"))
+    {
+      putchar ('\"');
+      fputs (hdr_version, stdout);
+      putchar ('\"');
+      putchar ('\n');
+    }
+  else if (!strcmp (tag, "version-number"))
+    {
+      fputs (hdr_version_number, stdout);
+      putchar ('\n');
+    }
+  else if (!strcmp (tag, "include:err-sources"))
+    {
+      write_sources_or_codes (NULL);
+      include_file (fname, lnr, "err-sources.h.in", write_sources_or_codes);
+    }
+  else if (!strcmp (tag, "include:err-codes"))
+    {
+      write_sources_or_codes (NULL);
+      include_file (fname, lnr, "err-codes.h.in", write_sources_or_codes);
+    }
+  else if (!strcmp (tag, "include:errnos"))
+    {
+      include_file (fname, lnr, "errnos.in", write_errnos_in);
+    }
+  else if (!strcmp (tag, "include:os-add"))
+    {
+      if (!strcmp (host_os, "mingw32"))
+        {
+          include_file (fname, lnr, "w32-add.h", write_line);
+        }
+      else if (!strcmp (host_os, "mingw32ce"))
+        {
+          include_file (fname, lnr, "w32-add.h", write_line);
+          include_file (fname, lnr, "w32ce-add.h", write_line);
+        }
+    }
+  else
+    return 0; /* Unknown tag.  */
+
+  return 1; /* Tag processed.  */
+}
+
+
+int
+main (int argc, char **argv)
+{
+  FILE *fp;
+  char line[LINESIZE];
+  int lnr = 0;
+  const char *fname, *s;
+  char *p1, *p2;
+
+  if (argc)
+    {
+      argc--; argv++;
+    }
+
+  if (argc != 4)
+    {
+      fputs ("usage: " PGM " host_os template.h version version_number\n",
+             stderr);
+      return 1;
+    }
+  host_os = argv[0];
+  fname = argv[1];
+  hdr_version = argv[2];
+  hdr_version_number = argv[3];
+
+  srcdir = malloc (strlen (fname) + 2 + 1);
+  if (!srcdir)
+    {
+      fputs (PGM ": out of core\n", stderr);
+      return 1;
+    }
+  strcpy (srcdir, fname);
+  p1 = strrchr (srcdir, '/');
+  if (p1)
+    p1[1] = 0;
+  else
+    strcpy (srcdir, "./");
+
+  fp = fopen (fname, "r");
+  if (!fp)
+    {
+      fprintf (stderr, "%s:%d: can't open file: %s",
+               fname, lnr, strerror (errno));
+      return 1;
+    }
+
+  while (fgets (line, LINESIZE, fp))
+    {
+      size_t n = strlen (line);
+
+      lnr++;
+      if (!n || line[n-1] != '\n')
+        {
+          fprintf (stderr,
+                   "%s:%d: trailing linefeed missing, line too long or "
+                   "embedded nul character\n", fname, lnr);
+          break;
+        }
+      line[--n] = 0;
+
+      p1 = strchr (line, '@');
+      p2 = p1? strchr (p1+1, '@') : NULL;
+      if (!p1 || !p2 || p2-p1 == 1)
+        {
+          puts (line);
+          continue;
+        }
+      *p1++ = 0;
+      *p2++ = 0;
+      fputs (line, stdout);
+
+      if (!strcmp (p1, "configure_input"))
+        {
+          s = strrchr (fname, '/');
+          printf ("Do not edit.  Generated from %s by %s for %s.",
+                  s? s+1 : fname, PGM, host_os);
+          fputs (p2, stdout);
+          putchar ('\n');
+        }
+      else if (!write_special (fname, lnr, p1))
+        {
+          putchar ('@');
+          fputs (p1, stdout);
+          putchar ('@');
+          fputs (p2, stdout);
+          putchar ('\n');
+        }
+    }
+
+  if (ferror (fp))
+    {
+      fprintf (stderr, "%s:%d: error reading file: %s\n",
+               fname, lnr, strerror (errno));
+      return 1;
+    }
+
+  fputs ("/*\n"
+         "Loc" "al Variables:\n"
+         "buffer-read-only: t\n"
+         "End:\n"
+         "*/\n", stdout);
+
+  if (ferror (stdout))
+    {
+      fprintf (stderr, PGM ": error writing to stdout: %s\n", strerror (errno));
+      return 1;
+    }
+
+  fclose (fp);
+
+  return 0;
+}