--- include/sane/sanei_udp.h
+++ include/sane/sanei_udp.h
@@ -27,6 +27,9 @@
 #include <netinet/in.h>
 #include <netdb.h>
 #endif
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 
 extern SANE_Status sanei_udp_open(const char *host, int port, int *fdp);
 extern SANE_Status sanei_udp_open_broadcast(int *fdp);
--- backend/kvs20xx_cmd.h
+++ backend/kvs20xx_cmd.h
@@ -9,6 +9,10 @@
    Panasonic KV-S20xx USB-SCSI scanners.
 */
 
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+
 #define COMMAND_BLOCK	1
 #define DATA_BLOCK	2
 #define RESPONSE_BLOCK	3
--- backend/kvs40xx.h
+++ backend/kvs40xx.h
@@ -10,6 +10,9 @@
 
 #include "../include/sane/config.h"
 #include <semaphore.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 
 #undef  BACKEND_NAME
 #define BACKEND_NAME kvs40xx
--- backend/hp5400.c
+++ backend/hp5400.c
@@ -67,6 +67,9 @@
 #include <stdlib.h>		/* malloc, free */
 #include <string.h>		/* memcpy */
 #include <stdio.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 
 
 #define HP5400_CONFIG_FILE "hp5400.conf"
--- backend/hp5590.c
+++ backend/hp5590.c
@@ -48,6 +48,9 @@
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 
 #include "../include/sane/sane.h"
 #define BACKEND_NAME hp5590
--- backend/epsonds-io.c
+++ backend/epsonds-io.c
@@ -16,6 +16,9 @@
 #include "sane/config.h"
 #include <ctype.h>
 #include <unistd.h>     /* sleep */
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
 
 #include "epsonds.h"
 #include "epsonds-io.h"
