diff --git a/psycopg/lobject_int.c b/psycopg/lobject_int.c
index f66d9498..86aa9012 100644
--- a/psycopg/lobject_int.c
+++ b/psycopg/lobject_int.c
@@ -389,7 +389,7 @@ lobject_seek(lobjectObject *self, long pos, int whence)
     Py_BEGIN_ALLOW_THREADS;
     pthread_mutex_lock(&(self->conn->lock));
 
-#if HAVE_LO64
+#ifdef HAVE_LO64
     if (self->conn->server_version < 90300) {
         where = (long)lo_lseek(self->conn->pgconn, self->fd, (int)pos, whence);
     } else {
@@ -424,7 +424,7 @@ lobject_tell(lobjectObject *self)
     Py_BEGIN_ALLOW_THREADS;
     pthread_mutex_lock(&(self->conn->lock));
 
-#if HAVE_LO64
+#ifdef HAVE_LO64
     if (self->conn->server_version < 90300) {
         where = (long)lo_tell(self->conn->pgconn, self->fd);
     } else {
@@ -489,7 +489,7 @@ lobject_truncate(lobjectObject *self, size_t len)
     Py_BEGIN_ALLOW_THREADS;
     pthread_mutex_lock(&(self->conn->lock));
 
-#if HAVE_LO64
+#ifdef HAVE_LO64
     if (self->conn->server_version < 90300) {
         retvalue = lo_truncate(self->conn->pgconn, self->fd, len);
     } else {
diff --git a/psycopg/lobject_type.c b/psycopg/lobject_type.c
index 82aa186d..a25240c1 100644
--- a/psycopg/lobject_type.c
+++ b/psycopg/lobject_type.c
@@ -175,7 +175,7 @@ psyco_lobj_seek(lobjectObject *self, PyObject *args)
     EXC_IF_LOBJ_LEVEL0(self);
     EXC_IF_LOBJ_UNMARKED(self);
 
-#if !HAVE_LO64
+#ifndef HAVE_LO64
     if (offset > INT_MAX) {
         psyco_set_error(InterfaceError, NULL,
             "offset out of range");
@@ -272,7 +272,7 @@ psyco_lobj_truncate(lobjectObject *self, PyObject *args)
     EXC_IF_LOBJ_LEVEL0(self);
     EXC_IF_LOBJ_UNMARKED(self);
 
-#if !HAVE_LO64
+#ifndef HAVE_LO64
     if (len > INT_MAX) {
         psyco_set_error(InterfaceError, NULL,
             "len out of range");
diff --git a/setup.py b/setup.py
index 9e797cda..647a532f 100644
--- a/setup.py
+++ b/setup.py
@@ -422,8 +422,6 @@ class psycopg_build_ext(build_ext):
             # enable lo64 if postgres >= 9.3
             if (pgmajor, pgminor) >= (9, 3):
                 define_macros.append(("HAVE_LO64", "1"))
-            else:
-                define_macros.append(("HAVE_LO64", "0"))
 
         except Warning:
             w = sys.exc_info()[1]  # work around py 2/3 different syntax