Configure checks for chown; add missing shields in code.

Upstream status: not yet presented upstream.

--- readline-7.0/histfile.c.orig	2016-12-06 20:04:10.058901731 +0100
+++ readline-7.0/histfile.c	2016-12-06 20:05:09.220083801 +0100
@@ -610,8 +610,10 @@
      user is running this, it's a no-op.  If the shell is running after sudo
      with a shared history file, we don't want to leave the history file
      owned by root. */
+#if HAVE_CHOWN
   if (rv == 0 && exists)
     r = chown (filename, finfo.st_uid, finfo.st_gid);
+#endif
 
   xfree (filename);
   FREE (tempname);
@@ -757,8 +759,10 @@
      user is running this, it's a no-op.  If the shell is running after sudo
      with a shared history file, we don't want to leave the history file
      owned by root. */
+#if HAVE_CHOWN
   if (rv == 0 && exists)
     mode = chown (histname, finfo.st_uid, finfo.st_gid);
+#endif
 
   FREE (histname);
   FREE (tempname);
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<tr><td><span title='2023-01-30 12:39:40 +0200'>2023-01-30</span></td><td><a href='/guix/commit/gnu/packages/pciutils.scm?id=4cf1acc7f3033b50b0bf19e02c9f522d522d338c'>Merge remote-tracking branch 'origin/master' into core-updates</a><span class='msg-avail'>...<span class='msg-tooltip'> Conflicts:
	doc/guix.texi
	gnu/local.mk
	gnu/packages/admin.scm
	gnu/packages/base.scm
	gnu/packages/chromium.scm
	gnu/packages/compression.scm
	gnu/packages/databases.scm
	gnu/packages/diffoscope.scm
	gnu/packages/freedesktop.scm
	gnu/packages/gnome.scm
	gnu/packages/gnupg.scm
	gnu/packages/guile.scm
	gnu/packages/inkscape.scm
	gnu/packages/llvm.scm
	gnu/packages/openldap.scm
	gnu/packages/pciutils.scm
	gnu/packages/ruby.scm
	gnu/packages/samba.scm
	gnu/packages/sqlite.scm
	gnu/packages/statistics.scm
	gnu/packages/syndication.scm
	gnu/packages/tex.scm
	gnu/packages/tls.scm
	gnu/packages/version-control.scm
	gnu/packages/xml.scm
	guix/build-system/copy.scm
	guix/scripts/home.scm
</span></span></td><td>Efraim Flashner</td></tr>