diff --git a/unix/m4/lib-ld.m4 b/unix/m4/lib-ld.m4
new file mode 100644
index 0000000..96c4e2c
--- /dev/null
+++ b/unix/m4/lib-ld.m4
@@ -0,0 +1,110 @@
+# lib-ld.m4 serial 3 (gettext-0.13)
+dnl Copyright (C) 1996-2003 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Subroutines of libtool.m4,
+dnl with replacements s/AC_/AC_LIB/ and s/lt_cv/acl_cv/ to avoid collision
+dnl with libtool.m4.
+
+dnl From libtool-1.4. Sets the variable with_gnu_ld to yes or no.
+AC_DEFUN([AC_LIB_PROG_LD_GNU],
+[AC_CACHE_CHECK([if the linker ($LD) is GNU ld], acl_cv_prog_gnu_ld,
+[# I'd rather use --version here, but apparently some GNU ld's only accept -v.
+case `$LD -v 2>&1 </dev/null` in
+*GNU* | *'with BFD'*)
+  acl_cv_prog_gnu_ld=yes ;;
+*)
+  acl_cv_prog_gnu_ld=no ;;
+esac])
+with_gnu_ld=$acl_cv_prog_gnu_ld
+])
+
+dnl From libtool-1.4. Sets the variable LD.
+AC_DEFUN([AC_LIB_PROG_LD],
+[AC_ARG_WITH(gnu-ld,
+[  --with-gnu-ld           assume the C compiler uses GNU ld [default=no]],
+test "$withval" = no || with_gnu_ld=yes, with_gnu_ld=no)
+AC_REQUIRE([AC_PROG_CC])dnl
+AC_REQUIRE([AC_CANONICAL_HOST])dnl
+# Prepare PATH_SEPARATOR.
+# The user is always right.
+if test "${PATH_SEPARATOR+set}" != set; then
+  echo "#! /bin/sh" >conf$$.sh
+  echo  "exit 0"   >>conf$$.sh
+  chmod +x conf$$.sh
+  if (PATH="/nonexistent;."; conf$$.sh) >/dev/null 2>&1; then
+    PATH_SEPARATOR=';'
+  else
+    PATH_SEPARATOR=:
+  fi
+  rm -f conf$$.sh
+fi
+ac_prog=ld
+if test "$GCC" = yes; then
+  # Check if gcc -print-prog-name=ld gives a path.
+  AC_MSG_CHECKING([for ld used by GCC])
+  case $host in
+  *-*-mingw*)
+    # gcc leaves a trailing carriage return which upsets mingw
+    ac_prog=`($CC -print-prog-name=ld) 2>&5 | tr -d '\015'` ;;
+  *)
+    ac_prog=`($CC -print-prog-name=ld) 2>&5` ;;
+  esac
+  case $ac_prog in
+    # Accept absolute paths.
+    [[\\/]* | [A-Za-z]:[\\/]*)]
+      [re_direlt='/[^/][^/]*/\.\./']
+      # Canonicalize the path of ld
+      ac_prog=`echo $ac_prog| sed 's%\\\\%/%g'`
+      while echo $ac_prog | grep "$re_direlt" > /dev/null 2>&1; do
+	ac_prog=`echo $ac_prog| sed "s%$re_direlt%/%"`
+      done
+      test -z "$LD" && LD="$ac_prog"
+      ;;
+  "")
+    # If it fails, then pretend we aren't using GCC.
+    ac_prog=ld
+    ;;
+  *)
+    # If it is relative, then search for the first ld in PATH.
+    with_gnu_ld=unknown
+    ;;
+  esac
+elif test "$with_gnu_ld" = yes; then
+  AC_MSG_CHECKING([for GNU ld])
+else
+  AC_MSG_CHECKING([for non-GNU ld])
+fi
+AC_CACHE_VAL(acl_cv_path_LD,
+[if test -z "$LD"; then
+  IFS="${IFS= 	}"; ac_save_ifs="$IFS"; IFS="${IFS}${PATH_SEPARATOR-:}"
+  for ac_dir in $PATH; do
+    test -z "$ac_dir" && ac_dir=.
+    if test -f "$ac_dir/$ac_prog" || test -f "$ac_dir/$ac_prog$ac_exeext"; then
+      acl_cv_path_LD="$ac_dir/$ac_prog"
+      # Check to see if the program is GNU ld.  I'd rather use --version,
+      # but apparently some GNU ld's only accept -v.
+      # Break only if it was the GNU/non-GNU ld that we prefer.
+      case `"$acl_cv_path_LD" -v 2>&1 < /dev/null` in
+      *GNU* | *'with BFD'*)
+	test "$with_gnu_ld" != no && break ;;
+      *)
+	test "$with_gnu_ld" != yes && break ;;
+      esac
+    fi
+  done
+  IFS="$ac_save_ifs"
+else
+  acl_cv_path_LD="$LD" # Let the user override the test with a path.
+fi])
+LD="$acl_cv_path_LD"
+if test -n "$LD"; then
+  AC_MSG_RESULT($LD)
+else
+  AC_MSG_RESULT(no)
+fi
+test -z "$LD" && AC_MSG_ERROR([no acceptable ld found in \$PATH])
+AC_LIB_PROG_LD_GNU
+])