OpenWrt automake patch

- Error
Unescaped left brace in regex is illegal here in regex; marked by <-- HERE in m/\${ <-- HERE ([^ \t=:+{}]+)}/ at ./bin/automake.tmp line 3938.


- Patch
tools/automake/patches$ cat 0002-port-to-perl-5.22-and-later.patch
Without this change, Perl 5.22 complains "Unescaped left brace in
regex is deprecated" and this is planned to become a hard error in
Perl 5.26.  See:
http://search.cpan.org/dist/perl-5.22.0/pod/perldelta.pod#A_literal_%22{%22_should_now_be_escaped_in_a_pattern
* bin/automake.in (substitute_ac_subst_variables): Escape left brace.

Backported from:
http://git.savannah.gnu.org/cgit/automake.git/commit/?id=13f00eb4493c217269b76614759e452d8302955e
Original author: Paul Eggert <eggert@cs.ucla.edu>
Signed-off-by: Adam Duskett <aduskett@gmail.com>

diff --git a/bin/automake.in b/bin/automake.in
index a3a0aa3..2c8f31e 100644
--- a/bin/automake.in
+++ b/bin/automake.in
@@ -3878,7 +3878,7 @@ sub substitute_ac_subst_variables_worker
 sub substitute_ac_subst_variables
 {
   my ($text) = @_;
-  $text =~ s/\${([^ \t=:+{}]+)}/substitute_ac_subst_variables_worker ($1)/ge;
+  $text =~ s/\$[{]([^ \t=:+{}]+)}/substitute_ac_subst_variables_worker ($1)/ge;
   return $text;
 }