maint: remove from VC two gnulib-provided files

* build-aux/link-warning.h: Remove file from version control.
* build-aux/mktempd: Likewise.
* build-aux/.gitignore: Adjust.

build-aux/.gitignore

-compile
-config.guess
-config.rpath
-config.sub
-depcomp
-install-sh
-ltmain.sh
-missing
-mkinstalldirs
-mktempd
-/useless-if-before-free
-/vc-list-files
-/gitlog-to-changelog
+*

build-aux/link-warning.h

-/* GL_LINK_WARNING("literal string") arranges to emit the literal string as
-   a linker warning on most glibc systems.
-   We use a linker warning rather than a preprocessor warning, because
-   #warning cannot be used inside macros.  */
-#ifndef GL_LINK_WARNING
-  /* This works on platforms with GNU ld and ELF object format.
-     Testing __GLIBC__ is sufficient for asserting that GNU ld is in use.
-     Testing __ELF__ guarantees the ELF object format.
-     Testing __GNUC__ is necessary for the compound expression syntax.  */
-# if defined __GLIBC__ && defined __ELF__ && defined __GNUC__
-#  define GL_LINK_WARNING(message) \
-     GL_LINK_WARNING1 (__FILE__, __LINE__, message)
-#  define GL_LINK_WARNING1(file, line, message) \
-     GL_LINK_WARNING2 (file, line, message)  /* macroexpand file and line */
-#  define GL_LINK_WARNING2(file, line, message) \
-     GL_LINK_WARNING3 (file ":" #line ": warning: " message)
-#  define GL_LINK_WARNING3(message) \
-     ({ static const char warning[sizeof (message)]		\
-          __attribute__ ((__unused__,				\
-                          __section__ (".gnu.warning"),		\
-                          __aligned__ (1)))			\
-          = message "\n";					\
-        (void)0;						\
-     })
-# else
-#  define GL_LINK_WARNING(message) ((void) 0)
-# endif
-#endif

build-aux/mktempd

-#!/bin/sh
-# Create a temporary directory, much like mktemp -d does.
-
-# Copyright (C) 2007-2008 Free Software Foundation, Inc.
-
-# 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 3 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, see <http://www.gnu.org/licenses/>.
-
-# Written by Jim Meyering.
-
-# Usage: mktempd /tmp phoey.XXXXXXXXXX
-
-# First, try to use the mktemp program.
-# Failing that, we'll roll our own mktemp-like function:
-#  - try to get random bytes from /dev/urandom
-#  - failing that, generate output from a combination of quickly-varying
-#      sources and gzip.  Ignore non-varying gzip header, and extract
-#      "random" bits from there.
-#  - given those bits, map to file-name bytes using tr, and try to create
-#      the desired directory.
-#  - make only $MAX_TRIES attempts
-
-ME=`basename "$0"`
-die() { echo >&2 "$ME: $@"; exit 1; }
-
-MAX_TRIES=4
-
-rand_bytes()
-{
-  n=$1
-
-  chars=abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789
-
-  dev_rand=/dev/urandom
-  if test -r "$dev_rand"; then
-    # Note: 256-length($chars) == 194; 3 copies of $chars is 186 + 8 = 194.
-    dd ibs=$n count=1 if="$dev_rand" | tr -c $chars 01234567$chars$chars$chars
-    return
-  fi
-
-  cmds='date; date +%N; free; who -a; w; ps auxww; ps ef; netstat -n'
-  data=` (eval "$cmds") 2>&1 | gzip `
-
-  n_plus_50=`expr $n + 50`
-
-  # Ensure that $data has length at least 50+$n
-  while :; do
-    len=`echo "$data"|wc -c`
-    test $n_plus_50 -le $len && break;
-    data=` (echo "$data"; eval "$cmds") 2>&1 | gzip `
-  done
-
-  echo "$data" \
-    | dd bs=1 skip=50 count=$n 2>/dev/null \
-    | tr -c $chars 01234567$chars$chars$chars
-}
-
-mktempd()
-{
-  case $# in
-  2);;
-  *) die "Usage: $ME DIR TEMPLATE";;
-  esac
-
-  destdir=$1
-  template=$2
-
-  # Disallow any trailing slash on specified destdir:
-  # it would subvert the post-mktemp "case"-based destdir test.
-  case $destdir in
-  /) ;;
-  */) die "invalid destination dir: remove trailing slash(es)";;
-  esac
-
-  case $template in
-  *XXXX) ;;
-  *) die "invalid template: $template (must have a suffix of at least 4 X's)";;
-  esac
-
-  fail=0
-
-  # First, try to use mktemp.
-  d=`env -u TMPDIR mktemp -d -t -p "$destdir" "$template" 2>/dev/null` \
-    || fail=1
-
-  # The resulting name must be in the specified directory.
-  case $d in "$destdir"*);; *) fail=1;; esac
-
-  # It must have created the directory.
-  test -d "$d" || fail=1
-
-  # It must have 0700 permissions.  Handle sticky "S" bits.
-  perms=`ls -dgo "$d" 2>/dev/null|tr S -` || fail=1
-  case $perms in drwx------*) ;; *) fail=1;; esac
-
-  test $fail = 0 && {
-    echo "$d"
-    return
-  }
-
-  # If we reach this point, we'll have to create a directory manually.
-
-  # Get a copy of the template without its suffix of X's.
-  base_template=`echo "$template"|sed 's/XX*$//'`
-
-  # Calculate how many X's we've just removed.
-  template_length=`echo "$template" | wc -c`
-  nx=`echo "$base_template" | wc -c`
-  nx=`expr $template_length - $nx`
-
-  err=
-  i=1
-  while :; do
-    X=`rand_bytes $nx`
-    candidate_dir="$destdir/$base_template$X"
-    err=`mkdir -m 0700 "$candidate_dir" 2>&1` \
-      && { echo "$candidate_dir"; return; }
-    test $MAX_TRIES -le $i && break;
-    i=`expr $i + 1`
-  done
-  die "$err"
-}
-
-mktempd "$@"