[PATCH] remove invalid "tail +16c" in config/acx.m4

[ma.jiang@zte.com.cn]

Hi all,
  In "config/acx.m4", there are still some "tail +16c"  which are invalid 
on POSIX systems. 
  In my opinion， all "tail +16c" should be changed to "tail -c +16" 
directly, as most systems has accept the latter.
  And, to skip first 16 bytes, we should use "tail -c +17" instead of 
"tail -c +16".

                 * config/acx.m4:Change "tail +16c" to "tail -c +17".
                 * configure: Regenerate.
--- gcc-6.2.0/config/acx.m4     2011-12-18 17:58:37.000000000 +0800
+++ gcc-6.2.0-bak/config/acx.m4 2016-11-23 10:56:21.065817691 +0800
@@ -404,7 +404,7 @@ AC_DEFUN([ACX_PROG_CMP_IGNORE_INITIAL],
 [AC_CACHE_CHECK([how to compare bootstrapped objects], 
gcc_cv_prog_cmp_skip,
 [ echo abfoo >t1
   echo cdfoo >t2
-  gcc_cv_prog_cmp_skip='tail +16c $$f1 > tmp-foo1; tail +16c $$f2 > 
tmp-foo2; cmp tmp-foo1 tmp-foo2'
+  gcc_cv_prog_cmp_skip='tail -c +17 $$f1 > tmp-foo1; tail -c +17 $$f2 > 
tmp-foo2; cmp tmp-foo1 tmp-foo2'
   if cmp t1 t2 2 2 > /dev/null 2>&1; then
     if cmp t1 t2 1 1 > /dev/null 2>&1; then
       :