diff --git a/acinclude.m4 b/acinclude.m4
index 9c7f451..922e5d1 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -484,6 +484,7 @@ dnl
       AC_TRY_RUN([
 #include <sane/sane.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 int 
 main ()
diff --git a/aclocal.m4 b/aclocal.m4
index b83ffbb..88829e4 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -494,6 +494,7 @@ dnl
       AC_TRY_RUN([
 #include <sane/sane.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 int 
 main ()
diff --git a/configure b/configure
index 427c259..71c3fa8 100755
--- a/configure
+++ b/configure
@@ -4864,7 +4864,7 @@ fi
 
 
 
-for ac_header in os2.h fcntl.h unistd.h libc.h sys/time.h sys/types.h
+for ac_header in os2.h fcntl.h unistd.h libc.h sys/time.h sys/types.h sys/socket.h
 do
 as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 if { as_var=$as_ac_Header; eval "test \"\${$as_var+set}\" = set"; }; then
@@ -7565,6 +7565,7 @@ cat >>conftest.$ac_ext <<_ACEOF
 
 #include <sane/sane.h>
 #include <stdio.h>
+#include <stdlib.h>
 
 int
 main ()
diff --git a/include/sane/config.h.in b/include/sane/config.h.in
index baf35be..b8d901d 100644
--- a/include/sane/config.h.in
+++ b/include/sane/config.h.in
@@ -108,6 +108,9 @@
 /* Define to 1 if you have the `strtod' function. */
 #undef HAVE_STRTOD
 
+/* Define to 1 if you have the <sys/socket.h> header file. */
+#undef HAVE_SYS_SOCKET_H
+
 /* Define to 1 if you have the <sys/stat.h> header file. */
 #undef HAVE_SYS_STAT_H