choose our openldap paths, do not clash with Mozilla ldap

diff --git a/m4/ldap.m4 b/m4/ldap.m4
index e7659bd..e586598 100644
--- a/m4/ldap.m4
+++ b/m4/ldap.m4
@@ -73,16 +73,16 @@ AS_HELP_STRING([--with-ldap@<:@=DIR@:>@],[Include LDAP support @<:@default=no@:>
      ],[_libldap_with=ifelse([$1],,[no],[$1])])
 
   if test "x$_libldap_with" != x"no"; then
-        AC_MSG_CHECKING([for LDAP support of ldap.h])
+        AC_MSG_CHECKING([for OpenLDAP support of ldap.h])
 
         if test "$_libldap_with" = "yes"; then
                 if test -f /usr/local/openldap/include/ldap.h; then
                         LDAP_INCDIR=/usr/local/openldap/include/
                         LDAP_LIBDIR=/usr/local/openldap/lib/
                         found_ldap="yes"
-                elif test -f /usr/include/ldap.h; then
-                        LDAP_INCDIR=/usr/include
-                        LDAP_LIBDIR=/usr/lib
+                elif test -f /usr/include/openldap/ldap.h; then
+                        LDAP_INCDIR=/usr/include/openldap
+                        LDAP_LIBDIR=/usr/lib/amd64/openldap
                         found_ldap="yes"
                 elif test -f /usr/local/include/ldap.h; then
                         LDAP_INCDIR=/usr/local/include