patches/openwrt: lldpd: backport patch from master branch

patches/openwrt/backport/0006-lldpd-fix-autoreconf-failure.patch

+From dd5b3b58d8aa4427c40bc1247196a6693a57f460 Mon Sep 17 00:00:00 2001
+From: Jo-Philipp Wich <jo@mein.io>
+Date: Wed, 9 Dec 2020 11:53:04 +0100
+Subject: [PATCH] lldpd: fix autoreconf failure
+
+The lldpd sources ship a modified local AX_LIB_READLINE M4 macro which
+conflicts with the official macro shipped by autoconf-archive.
+
+Due to the official macro having the same name and a higher serial
+number, autoconf will prefer including that one instead of the local
+copy, preventing the substitution of @READLINE_LIBS@ in Makefile.in
+templates, ultimately leading to the following build failure when
+linking lldpcli:
+
+    ...-gcc: error: READLINE_LIBS@: No such file or directory
+
+Avoid this problem by renaming the locally shipped macro to not clash
+with the official implementation anymore.
+
+Ref: https://github.com/lldpd/lldpd/pull/423
+Acked-by: Stijn Tintel <stijn@linux-ipv6.be>
+Tested-by: Rosen Penev <rosenp@gmail.com>
+Signed-off-by: Jo-Philipp Wich <jo@mein.io>
+---
+ ...2-fix-AX_LIB_READLINE-macro-conflict.patch | 61 +++++++++++++++++++
+ 1 file changed, 61 insertions(+)
+ create mode 100644 package/network/services/lldpd/patches/002-fix-AX_LIB_READLINE-macro-conflict.patch
+
+diff --git a/package/network/services/lldpd/patches/002-fix-AX_LIB_READLINE-macro-conflict.patch b/package/network/services/lldpd/patches/002-fix-AX_LIB_READLINE-macro-conflict.patch
+new file mode 100644
+index 0000000000..9cdf66f2e7
+--- /dev/null
++++ b/package/network/services/lldpd/patches/002-fix-AX_LIB_READLINE-macro-conflict.patch
+@@ -0,0 +1,61 @@
++From 23509dc05b24a28fb46022800e0e271ae0118de2 Mon Sep 17 00:00:00 2001
++From: Jo-Philipp Wich <jo@mein.io>
++Date: Wed, 9 Dec 2020 12:04:04 +0100
++Subject: [PATCH] build: prevent conflict with official AX_LIB_READLINE macro
++
++On systems where the official AX_LIB_READLINE (ax_lib_readline.m4) is
++present in a globally shared autoconf include directory, auto(re)conf
++will prefer including that offical version over the local variant due
++to the offical macro having a higher serial number.
++
++As a consequence, @READLINE_LIBS@ will not be substituted in *.in files,
++eventually failing the compilation with errors similar to:
++
++    gcc: error: READLINE_LIBS@: No such file or directory
++
++Avoid this problem by renaming the incompatible local macro to
++AX_LIB_READLINE_LLDPD which is sufficient to prevent any clashes.
++
++We encountered this problem on OpenWrt which uses GNU autoconf-archive
++to provide commonly used M4 macros through a global include directory,
++which happens to ship AX_LIB_READLINE as well.
++
++Signed-off-by: Jo-Philipp Wich <jo@mein.io>
++---
++ configure.ac          | 2 +-
++ m4/ax_lib_readline.m4 | 6 +++---
++ 2 files changed, 4 insertions(+), 4 deletions(-)
++
++--- a/configure.ac
+++++ b/configure.ac
++@@ -273,7 +273,7 @@ AC_ARG_WITH([readline],
++   [],
++   [with_readline=auto])
++ if test x"$with_readline" != x"no"; then
++-   AX_LIB_READLINE
+++   AX_LIB_READLINE_LLDPD
++    if test x"$with_readline" != x"check" -a x"$with_readline" != x"auto"; then
++      if test x"$ax_cv_lib_readline" = x"no"; then
++        AC_MSG_FAILURE([*** no readline support found])
++--- a/m4/ax_lib_readline.m4
+++++ b/m4/ax_lib_readline.m4
++@@ -4,7 +4,7 @@
++ #
++ # SYNOPSIS
++ #
++-#   AX_LIB_READLINE
+++#   AX_LIB_READLINE_LLDPD
++ #
++ # DESCRIPTION
++ #
++@@ -66,8 +66,8 @@
++ 
++ #serial 6
++ 
++-AU_ALIAS([VL_LIB_READLINE], [AX_LIB_READLINE])
++-AC_DEFUN([AX_LIB_READLINE], [
+++AU_ALIAS([VL_LIB_READLINE], [AX_LIB_READLINE_LLDPD])
+++AC_DEFUN([AX_LIB_READLINE_LLDPD], [
++   AC_CACHE_CHECK([for a readline compatible library],
++                  ax_cv_lib_readline, [
++     _save_LIBS="$LIBS"
+-- 
+2.25.1
+