From c1ddaf55d030e0e214c1359c8f8dc6ecbf9bee30 Mon Sep 17 00:00:00 2001
From: Ruben Kerkhof <ruben@rubenkerkhof.com>
Date: Sat, 27 May 2017 14:30:33 +0200
Subject: [PATCH] snmp-agent: fix build on RHEL6

libnetsnmpagent.so from net-snmp 5.5 needs some symbols from libnetsnmphelpers.so,
but does not link against it on RHEL5.

Work around this by looking for one of those symbols in the helper lib,
and if found, link against it.

Later versions of net-snmp seem to have moved those symbols to
libnetsnmpagent.so, so it's not an issue there.
---
 configure.ac | 88 ++++++++++++++++++++++++++++------------------------
 1 file changed, 48 insertions(+), 40 deletions(-)

diff --git a/configure.ac b/configure.ac
index 00735df4..102933c4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3770,22 +3770,22 @@ AC_SUBST([LIBNETAPP_LIBS])
 AC_ARG_WITH([libnetsnmp],
   [AS_HELP_STRING([--with-libnetsnmp@<:@=PREFIX@:>@], [Path to libnetsnmp.])],
   [
-	  if test "x$withval" = "xno"; then
-		  with_libnetsnmp="no"
-	  else if test "x$withval" = "xyes"; then
-		  with_libnetsnmp="yes"
-	  else
-		  with_libnetsnmp_cppflags="-I$withval/include"
-		  with_libnetsnmp_ldflags="-I$withval/lib"
-		  with_libnetsnmp="yes"
-	  fi; fi
+    if test "x$withval" = "xno"; then
+     with_libnetsnmp="no"
+    else if test "x$withval" = "xyes"; then
+     with_libnetsnmp="yes"
+    else
+      with_libnetsnmp_cppflags="-I$withval/include"
+      with_libnetsnmp_ldflags="-I$withval/lib"
+      with_libnetsnmp="yes"
+    fi; fi
   ],
   [with_libnetsnmp="yes"]
 )
 
 if test "x$with_libnetsnmp" = "xyes"; then
-	SAVE_CPPFLAGS="$CPPFLAGS"
-	CPPFLAGS="$CPPFLAGS $with_libnetsnmp_cppflags"
+  SAVE_CPPFLAGS="$CPPFLAGS"
+  CPPFLAGS="$CPPFLAGS $with_libnetsnmp_cppflags"
 
   AC_CHECK_HEADERS([net-snmp/net-snmp-config.h],
     [with_libnetsnmp="yes"],
@@ -3802,25 +3802,25 @@ if test "x$with_libnetsnmp" = "xyes"; then
     ]]
   )
 
-	CPPFLAGS="$SAVE_CPPFLAGS"
+  CPPFLAGS="$SAVE_CPPFLAGS"
 fi
 
 if test "x$with_libnetsnmp" = "xyes"; then
-	SAVE_LDFLAGS="$LDFLAGS"
-	LDFLAGS="$LDFLAGS $with_libnetsnmp_ldflags"
+  SAVE_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LDFLAGS $with_libnetsnmp_ldflags"
 
-	AC_CHECK_LIB([netsnmp], [init_snmp],
-		[],
-		[with_libnetsnmp="no (libnetsnmp not found)"]
+  AC_CHECK_LIB([netsnmp], [init_snmp],
+    [with_libnetsmp="yes"],
+    [with_libnetsnmp="no (libnetsnmp not found)"]
   )
 
-	LDFLAGS="$SAVE_LDFLAGS"
+  LDFLAGS="$SAVE_LDFLAGS"
 fi
 
 if test "x$with_libnetsnmp" = "xyes"; then
-	BUILD_WITH_LIBNETSNMP_CPPFLAGS="$with_libnetsnmp_cppflags"
-	BUILD_WITH_LIBNETSNMP_LDFLAGS="$with_libnetsnmp_ldflags"
-	BUILD_WITH_LIBNETSNMP_LIBS="-lnetsnmp"
+  BUILD_WITH_LIBNETSNMP_CPPFLAGS="$with_libnetsnmp_cppflags"
+  BUILD_WITH_LIBNETSNMP_LDFLAGS="$with_libnetsnmp_ldflags"
+  BUILD_WITH_LIBNETSNMP_LIBS="-lnetsnmp"
 fi
 
 AC_SUBST([BUILD_WITH_LIBNETSNMP_CPPFLAGS])
@@ -3832,22 +3832,22 @@ AC_SUBST([BUILD_WITH_LIBNETSNMP_LIBS])
 AC_ARG_WITH([libnetsnmpagent],
   [AS_HELP_STRING([--with-libnetsnmpagent@<:@=PREFIX@:>@], [Path to libnetsnmpagent.])],
   [
-	  if test "x$withval" = "xno"; then
-		  with_libnetsnmpagent="no"
-	  else if test "x$withval" = "xyes"; then
-		  with_libnetsnmpagent="yes"
-	  else
-		  with_libnetsnmpagent_cppflags="-I$withval/include"
-		  with_libnetsnmpagent_ldflags="-I$withval/lib"
-		  with_libnetsnmpagent="yes"
-	  fi; fi
+    if test "x$withval" = "xno"; then
+      with_libnetsnmpagent="no"
+    else if test "x$withval" = "xyes"; then
+      with_libnetsnmpagent="yes"
+    else
+      with_libnetsnmpagent_cppflags="-I$withval/include"
+      with_libnetsnmpagent_ldflags="-I$withval/lib"
+      with_libnetsnmpagent="yes"
+    fi; fi
   ],
   [with_libnetsnmpagent="yes"]
 )
 
 if test "x$with_libnetsnmpagent" = "xyes"; then
-	SAVE_CPPFLAGS="$CPPFLAGS"
-	CPPFLAGS="$CPPFLAGS $with_libnetsnmpagent_cppflags"
+  SAVE_CPPFLAGS="$CPPFLAGS"
+  CPPFLAGS="$CPPFLAGS $with_libnetsnmpagent_cppflags"
 
   AC_CHECK_HEADERS([net-snmp/agent/net-snmp-agent-includes.h],
     [],
@@ -3862,23 +3862,31 @@ if test "x$with_libnetsnmpagent" = "xyes"; then
     ]]
   )
 
-	CPPFLAGS="$SAVE_CPPFLAGS"
+  CPPFLAGS="$SAVE_CPPFLAGS"
 fi
 
 if test "x$with_libnetsnmpagent" = "xyes"; then
-	SAVE_LDFLAGS="$LDFLAGS"
-	LDFLAGS="$LDFLAGS $with_libnetsnmpagent_ldflags"
+  SAVE_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LDFLAGS $with_libnetsnmpagent_ldflags"
 
-	AC_CHECK_LIB([netsnmpagent], [init_agent],
-		[],
-		[with_libnetsnmpagent="no (libnetsnmpagent not found)"]
+  # older versions of libnetsnmpagent fail to link
+  # against the helpers library, so do that explicitly
+  AC_CHECK_LIB([netsnmphelpers], [netsnmp_init_helpers],
+    [libnetsnmphelpers="-lnetsnmphelpers"],
+    [libnetsnmphelpers=""]
   )
 
-	LDFLAGS="$SAVE_LDFLAGS"
+  AC_CHECK_LIB([netsnmpagent], [init_agent],
+    [with_libnetsnmpagent="yes"],
+    [with_libnetsnmpagent="no (libnetsnmpagent not found)"],
+    [$libnetsnmphelpers]
+  )
+
+  LDFLAGS="$SAVE_LDFLAGS"
 fi
 
 if test "x$with_libnetsnmpagent" = "xyes"; then
-	BUILD_WITH_LIBNETSNMPAGENT_LIBS="-lnetsnmpagent"
+  BUILD_WITH_LIBNETSNMPAGENT_LIBS="-lnetsnmpagent $libnetsnmphelpers"
 fi
 
 AC_SUBST([BUILD_WITH_LIBNETSNMPAGENT_CPPFLAGS])
-- 
2.30.2