diff --git a/iscsiuio/configure.ac b/iscsiuio/configure.ac
index b41df0e..a856cc5 100644
--- a/iscsiuio/configure.ac
+++ b/iscsiuio/configure.ac
@@ -67,10 +67,10 @@ AM_CONDITIONAL([DEBUG], [test x$debug = xtrue])
 AC_ARG_WITH([systemd],
 	    AS_HELP_STRING([--without-systemd], [Build without systemd]),
     [case "${withval}" in
-     yes) LDFLAGS="`pkg-config --libs libsystemd`" ;;
+     yes) LDFLAGS="${LDFLAGS} `pkg-config --libs libsystemd`" ;;
      no)  CFLAGS="${CFLAGS} -DNO_SYSTEMD" ;;
      *)   AC_MSG_ERROR([bad value $withval for --with-systemd]) ;;
-     esac],[LDFLAGS="`pkg-config --libs libsystemd`"])
+     esac],[LDFLAGS="${LDFLAGS} `pkg-config --libs libsystemd`"])
 
 AC_CONFIG_COMMANDS([default],[[
     if [ -n "$SOURCE_DATE_EPOCH" ] ; then