autogen: fix deprecated construct

Newer versions of Perl warn that unescaped left braces in regexps are
deprecated.

(cherry picked from commit open-mpi/ompi@9c9bad3)

Author: jsquyres

autogen.pl

@@ -1,6 +1,6 @@
 #!/usr/bin/env perl
 #
-# Copyright (c) 2009-2015 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2009-2016 Cisco Systems, Inc.  All rights reserved.
 # Copyright (c) 2010      Oracle and/or its affiliates.  All rights reserved.
 # Copyright (c) 2013      Mellanox Technologies, Inc.
 #                         All rights reserved.
@@ -1001,9 +1001,9 @@ sub patch_autotools_output {
     # https://github.com/open-mpi/ompi/issues/751
     push(@verbose_out, $indent_str . "Patching configure for libtool.m4 bug\n");
     # patch for libtool < 2.4.3
-    $c =~ s/# Some compilers place space between "-{L,R}" and the path.\n       # Remove the space.\n       if test \$p = \"-L\" \|\|/# Some compilers place space between "-{L,-l,R}" and the path.\n       # Remove the spaces.\n       if test \$p = \"-L\" \|\|\n          test \$p = \"-l\" \|\|/g;
+    $c =~ s/# Some compilers place space between "-\{L,R\}" and the path.\n       # Remove the space.\n       if test \$p = \"-L\" \|\|/# Some compilers place space between "-\{L,-l,R\}" and the path.\n       # Remove the spaces.\n       if test \$p = \"-L\" \|\|\n          test \$p = \"-l\" \|\|/g;
     # patch for libtool >= 2.4.3
-    $c =~ s/# Some compilers place space between "-{L,R}" and the path.\n       # Remove the space.\n       if test x-L = \"\$p\" \|\|\n          test x-R = \"\$p\"\; then/# Some compilers place space between "-{L,-l,R}" and the path.\n       # Remove the spaces.\n       if test x-L = \"x\$p\" \|\|\n          test x-l = \"x\$p\" \|\|\n          test x-R = \"x\$p\"\; then/g;
+    $c =~ s/# Some compilers place space between "-\{L,R\}" and the path.\n       # Remove the space.\n       if test x-L = \"\$p\" \|\|\n          test x-R = \"\$p\"\; then/# Some compilers place space between "-\{L,-l,R\}" and the path.\n       # Remove the spaces.\n       if test x-L = \"x\$p\" \|\|\n          test x-l = \"x\$p\" \|\|\n          test x-R = \"x\$p\"\; then/g;
 
     # Only write out verbose statements and a new configure if the
     # configure content actually changed