diff --git a/acinclude.m4 b/acinclude.m4
index 189ee95d11..142bffe6db 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1285,11 +1285,15 @@ AC_CHECK_SIZEOF(unsigned long)
 AC_CHECK_SIZEOF(unsigned int)
 AC_TYPE_INTPTR_T
 AC_TYPE_UINTPTR_T
-AC_CHECK_TYPES([ssize_t])
-AC_CHECK_TYPES([sig_atomic_t],[],[],
+AC_TYPE_SSIZE_T
+AC_CHECK_TYPE([sig_atomic_t],[],
+    [AC_DEFINE([sig_atomic_t], [int],
+        [Define to int if <signal.h> does not define.])],
 [#include <sys/types.h>
 #include <signal.h>])
-AC_CHECK_TYPES([socklen_t],[],[],
+AC_CHECK_TYPE([socklen_t],[],
+    [AC_DEFINE([socklen_t], [int],
+        [Define to int if <sys/socket.h> does not define.])],
 [#include <sys/types.h>
 #include <sys/socket.h>])
 AC_SIZEOF_TYPE(long)
diff --git a/src/config/stds.h b/src/config/stds.h
index d7358c5566..90f966152e 100644
--- a/src/config/stds.h
+++ b/src/config/stds.h
@@ -7,6 +7,12 @@
  * directory or online at http://www.openafs.org/dl/license10.html
  */
 
+/*
+ * Do not put anything in this file that relies on Autoconf defines, since
+ * we're not guaranteed to have included afsconfig.h before this header file.
+ * This is an installed header file, and afsconfig.h is not.
+ */
+
 #ifndef OPENAFS_AFS_CONFIG_STDS_H
 #define OPENAFS_AFS_CONFIG_STDS_H	1
 
@@ -51,18 +57,6 @@ pragma Off(Prototype_override_warnings);
 #define MIN_AFS_INT64 (-MAX_AFS_INT64 - 1)
 #define MAX_AFS_UINT64 0xFFFFFFFFFFFFFFFFL
 
-#ifndef HAVE_SSIZE_T
-typedef int ssize_t;
-#endif
-
-#ifndef HAVE_SIG_ATOMIC_T
-typedef int sig_atomic_t;
-#endif
-
-#ifndef HAVE_SOCKLEN_T
-typedef int socklen_t;
-#endif
-
 typedef short afs_int16;
 typedef unsigned short afs_uint16;
 #ifdef  AFS_64BIT_ENV