From c80502181f4a7bc5da11f1cdf9455443bb0fdd01 Mon Sep 17 00:00:00 2001
From: Mahesh Maddikayala <10645050+smaheshm@users.noreply.github.com>
Date: Mon, 19 Jul 2021 22:59:37 -0700
Subject: [PATCH] [configure.ac] Add the option of passing libnl path to
 configure script (#1824)

**What I did**
Add the option of passing custmol built libnl path to configure script

**Why I did it**
MPLS feature in sonic-buildimage requires a libnl patch to be applied before building libnl. Since this build is not installed in usual locations (/usr/lib/..) LGTM analysis fails. This change gives the option of passing libnl library location to 'configure' script and generate libraries to be linked.

In case the options are not passed, the configure script defaults to earlier behavior where it checks for LIBNL in usual locations
---
 configure.ac | 24 +++++++++++++++++++++---
 1 file changed, 21 insertions(+), 3 deletions(-)

diff --git a/configure.ac b/configure.ac
index d7816b6f17af..edca67de7c29 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13,8 +13,6 @@ AC_HEADER_STDC
 AC_CHECK_LIB([hiredis], [redisConnect],,
     AC_MSG_ERROR([libhiredis is not installed.]))
 
-AC_CHECK_LIB([nl-genl-3], [genl_connect])
-
 AC_CHECK_LIB([team], [team_alloc],
     AM_CONDITIONAL(HAVE_LIBTEAM, true),
    [AC_MSG_WARN([libteam is not installed.])
@@ -46,7 +44,27 @@ AC_ARG_WITH(extra-lib,
                           prefix where extra libraries are installed],
 [AC_SUBST(LDFLAGS, "$LDFLAGS -L${withval}")])
 
-CFLAGS_COMMON="-std=c++14 -Wall -fPIC -Wno-write-strings -I/usr/include/libnl3 -I/usr/include/swss"
+AC_ARG_WITH(extra-usr-lib,
+[  --with-extra-usr-lib=DIR
+                          prefix where extra libraries are installed],
+[AC_SUBST(LDFLAGS, "$LDFLAGS -L${withval}")])
+
+AC_CHECK_LIB([nl-3], [nl_addr_alloc])
+AC_CHECK_LIB([nl-genl-3], [nl_socket_get_cb])
+AC_CHECK_LIB([nl-route-3], [rtnl_route_nh_get_encap_mpls_dst])
+AC_CHECK_LIB([nl-nf-3], [nfnl_connect])
+
+CFLAGS_COMMON="-std=c++14 -Wall -fPIC -Wno-write-strings -I/usr/include/swss"
+
+AC_ARG_WITH(libnl-3.0-inc,
+[  --with-libnl-3.0-inc=DIR
+                           prefix where libnl-3.0 includes are installed],
+[AC_SUBST(CPPFLAGS, "$CPPFLAGS -I${withval}")
+ AC_SUBST(LIBNL_INC_DIR, "${withval}")])
+
+if test "${with_libnl_3_0_inc+set}" != set; then
+    CFLAGS_COMMON+=" -I/usr/include/libnl3"
+fi
 
 CFLAGS_COMMON+=" -Werror"
 CFLAGS_COMMON+=" -Wno-reorder"