Remove questionable build system sanity test which causes the build to
fail on Sierra.
--- aclocal.m4.orig	2002-08-20 01:01:53.000000000 -0500
+++ aclocal.m4	2016-10-24 09:20:01.000000000 -0500
@@ -43,49 +43,6 @@
 AM_MISSING_PROG(MAKEINFO, makeinfo, $missing_dir)
 AC_REQUIRE([AC_PROG_MAKE_SET])])
 
-#
-# Check to make sure that the build environment is sane.
-#
-
-AC_DEFUN([AM_SANITY_CHECK],
-[AC_MSG_CHECKING([whether build environment is sane])
-# Just in case
-sleep 1
-echo timestamp > conftestfile
-# Do `set' in a subshell so we don't clobber the current shell's
-# arguments.  Must try -L first in case configure is actually a
-# symlink; some systems play weird games with the mod time of symlinks
-# (eg FreeBSD returns the mod time of the symlink's containing
-# directory).
-if (
-   set X `ls -Lt $srcdir/configure conftestfile 2> /dev/null`
-   if test "[$]*" = "X"; then
-      # -L didn't work.
-      set X `ls -t $srcdir/configure conftestfile`
-   fi
-   if test "[$]*" != "X $srcdir/configure conftestfile" \
-      && test "[$]*" != "X conftestfile $srcdir/configure"; then
-
-      # If neither matched, then we have a broken ls.  This can happen
-      # if, for instance, CONFIG_SHELL is bash and it inherits a
-      # broken ls alias from the environment.  This has actually
-      # happened.  Such a system could not be considered "sane".
-      AC_MSG_ERROR([ls -t appears to fail.  Make sure there is not a broken
-alias in your environment])
-   fi
-
-   test "[$]2" = conftestfile
-   )
-then
-   # Ok.
-   :
-else
-   AC_MSG_ERROR([newly created file is older than distributed files!
-Check your system clock])
-fi
-rm -f conftest*
-AC_MSG_RESULT(yes)])
-
 dnl AM_MISSING_PROG(NAME, PROGRAM, DIRECTORY)
 dnl The program must properly implement --version.
 AC_DEFUN([AM_MISSING_PROG],