Use AC_SEARCH_LIBS for finding proper systemd library. (which is called libsystemd on most Linuxes, but libsystemd-daemon on Alt Linux SPT 7 and Debian Wheezy)

Author: vbwagner

configure

@@ -11302,6 +11302,64 @@ else
 fi
 
 
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing sd_notify" >&5
+$as_echo_n "checking for library containing sd_notify... " >&6; }
+if ${ac_cv_search_sd_notify+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sd_notify ();
+int
+main ()
+{
+return sd_notify ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' systemd systemd-daemon; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_sd_notify=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if ${ac_cv_search_sd_notify+:} false; then :
+  break
+fi
+done
+if ${ac_cv_search_sd_notify+:} false; then :
+
+else
+  ac_cv_search_sd_notify=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_sd_notify" >&5
+$as_echo "$ac_cv_search_sd_notify" >&6; }
+ac_res=$ac_cv_search_sd_notify
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+else
+  as_fn_error $? "Cannot find systemd library" "$LINENO" 5
+fi
+
 fi
 
 if test "$with_libxml" = yes ; then

configure.in

@@ -1303,6 +1303,7 @@ fi
 
 if test "$with_systemd" = yes ; then
   AC_CHECK_HEADER(systemd/sd-daemon.h, [], [AC_MSG_ERROR([header file <systemd/sd-daemon.h> is required for systemd support])])
+  AC_SEARCH_LIBS([sd_notify],[systemd systemd-daemon],[],[AC_MSG_ERROR([Cannot find systemd library])])
 fi
 
 if test "$with_libxml" = yes ; then

src/backend/Makefile

@@ -45,9 +45,6 @@ LIBS := $(filter-out -lpgport -lpgcommon, $(LIBS)) $(LDAP_LIBS_BE) $(ICU_LIBS)
 # The backend doesn't need everything that's in LIBS, however
 LIBS := $(filter-out -lreadline -ledit -ltermcap -lncurses -lcurses, $(LIBS)) 
 
-ifeq ($(with_systemd),yes)
-LIBS += -lsystemd
-endif
 
 ifeq ($(with_zstd),yes)
 LIBS += -lzstd