Subject: Re: BUG #17083: [PATCH] PostgreSQL fails to build with OpenLDAP 2.5.x
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-bugs@lists.postgresql.org
References: <17083-a19190d9591946a7@postgresql.org>
 <1666182.1625579201@sss.pgh.pa.us>
 <cc729116-2a2d-9edd-a32d-4066b92e4a75@03s.net>
 <1677203.1625582865@sss.pgh.pa.us>
From: Adrian Ho <ml+postgresql@03s.net>
Message-ID: <e78eb1f9-57b1-dae9-39c8-5dd72268be89@03s.net>
Date: Wed, 7 Jul 2021 15:54:59 +0800
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On 6/7/21 10:47 pm, Tom Lane wrote:
> Looking at the Autoconf docs, what AC_SEARCH_LIBS is specified to do is
> "Prepend `-lLIBRARY' to `LIBS' for the first library found to contain
> FUNCTION".  So I'd suggest
> 
> * Save contents of LIBS and set it to empty
> * Run AC_SEARCH_LIBS
> * LDAP_LIBS_FE="$LIBS $EXTRA_LDAP_LIBS"
> * Restore LIBS
> 
> I think we have some instances of that pattern already.

Thanks, Tom, that turned out to only require one additional line, since 
$LIBS is already being saved and restored around that block:

diff --git a/configure.in b/configure.in
index 14a6be6..842d61b 100644
--- a/configure.in
+++ b/configure.in
@@ -1241,17 +1241,20 @@ fi
  if test "$with_ldap" = yes ; then
    _LIBS="$LIBS"
    if test "$PORTNAME" != "win32"; then
-    AC_CHECK_LIB(ldap, ldap_bind, [],
-		 [AC_MSG_ERROR([library 'ldap' is required for LDAP])],
-		 [$EXTRA_LDAP_LIBS])
-    LDAP_LIBS_BE="-lldap $EXTRA_LDAP_LIBS"
      if test "$enable_thread_safety" = yes; then
        # on some platforms ldap_r fails to link without PTHREAD_LIBS
-      AC_CHECK_LIB(ldap_r, ldap_simple_bind, [],
-		   [AC_MSG_ERROR([library 'ldap_r' is required for LDAP])],
+      # OpenLDAP 2.5 merged ldap_r with ldap
+      LIBS=""
+      AC_SEARCH_LIBS(ldap_simple_bind, [ldap_r ldap], [],
+		   [AC_MSG_ERROR([not found in any LDAP library])],
  		   [$PTHREAD_CFLAGS $PTHREAD_LIBS $EXTRA_LDAP_LIBS])
-      LDAP_LIBS_FE="-lldap_r $EXTRA_LDAP_LIBS"
+      LDAP_LIBS_BE="-lldap $EXTRA_LDAP_LIBS"
+      LDAP_LIBS_FE="$LIBS $EXTRA_LDAP_LIBS"
      else
+      AC_CHECK_LIB(ldap, ldap_bind, [],
+		   [AC_MSG_ERROR([library 'ldap' is required for LDAP])],
+		   [$EXTRA_LDAP_LIBS])
+      LDAP_LIBS_BE="-lldap $EXTRA_LDAP_LIBS"
        LDAP_LIBS_FE="-lldap $EXTRA_LDAP_LIBS"
      fi
      AC_CHECK_FUNCS([ldap_initialize])


-- 
Best Regards,
Adrian