From eea19ad17c5f0a57478dcc336c916cb5d03c7274 Mon Sep 17 00:00:00 2001
From: Tomek Mrugalski <tomasz@isc.org>
Date: Thu, 15 Aug 2019 20:41:24 +0200
Subject: [PATCH] [#625,!485] Fixed conditional intialization detection for
 log4cplus

---
 configure.ac | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/configure.ac b/configure.ac
index 0a15f6c48f..aff9787ab7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1030,6 +1030,12 @@ AC_MSG_RESULT([$LOG4CPLUS_VERSION])
 CPPFLAGS=$CPPFLAGS_SAVED
 LIBS=$LIBS_SAVED
 
+# Older log4cplus versions (1.2.0) don't have the initializer.h header that
+# would allow explicit initialization. Newer versions (2.0.4 for sure, possibly
+# older as well) have it and it's recommended to use it. We detect whether
+# it's present or not and do explicit initalization if possible.
+LIBS_SAVED="$LIBS"
+LIBS="$LOG4CPLUS_LIBS $LIBS"
 AC_MSG_CHECKING([log4cplus explicit initialization (log4cplus/initializer.h)])
 AC_LINK_IFELSE(
         [AC_LANG_PROGRAM([#include <log4cplus/initializer.h>],
@@ -1038,6 +1044,7 @@ AC_LINK_IFELSE(
         [AC_MSG_RESULT([yes])
          AC_DEFINE(LOG4CPLUS_INITIALIZER_H, [1], [Explicit initialization of log4cplus possible])],
         [AC_MSG_RESULT(no)])
+LIBS="$LIBS_SAVED"
 
 #
 # Configure Boost header path
-- 
2.47.3