diff --git a/pyconfig.h.in b/pyconfig.h.in
index eb25449966a..9df729a0efc 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -5,9 +5,6 @@
 #define Py_PYCONFIG_H
 
 
-/* Define if building universal (internal helper macro) */
-#undef AC_APPLE_UNIVERSAL_BUILD
-
 /* Define for AIX if your compiler is a genuine IBM xlC/xlC_r and you want
    support for AIX C++ shared extension modules. */
 #undef AIX_GENUINE_CPLUSPLUS
@@ -491,9 +488,6 @@
 /* Define if your compiler supports function prototype */
 #undef HAVE_PROTOTYPES
 
-/* Define if you have GNU PTH threads. */
-#undef HAVE_PTH
-
 /* Defined for Solaris 2.6 bug in pthread header. */
 #undef HAVE_PTHREAD_DESTRUCTOR
 
@@ -1013,28 +1007,6 @@
 /* Define if you want to use computed gotos in ceval.c. */
 #undef USE_COMPUTED_GOTOS
 
-/* Enable extensions on AIX 3, Interix.  */
-#ifndef _ALL_SOURCE
-# undef _ALL_SOURCE
-#endif
-/* Enable GNU extensions on systems that have them.  */
-#ifndef _GNU_SOURCE
-# undef _GNU_SOURCE
-#endif
-/* Enable threading extensions on Solaris.  */
-#ifndef _POSIX_PTHREAD_SEMANTICS
-# undef _POSIX_PTHREAD_SEMANTICS
-#endif
-/* Enable extensions on HP NonStop.  */
-#ifndef _TANDEM_SOURCE
-# undef _TANDEM_SOURCE
-#endif
-/* Enable general extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
-#endif
-
-
 /* Define if a va_list is an array of some kind */
 #undef VA_LIST_IS_ARRAY
 
@@ -1072,21 +1044,20 @@
 /* Define to profile with the Pentium timestamp counter */
 #undef WITH_TSC
 
-/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
-   significant byte first (like Motorola and SPARC, unlike Intel). */
-#if defined AC_APPLE_UNIVERSAL_BUILD
-# if defined __BIG_ENDIAN__
-#  define WORDS_BIGENDIAN 1
-# endif
-#else
-# ifndef WORDS_BIGENDIAN
-#  undef WORDS_BIGENDIAN
-# endif
-#endif
+/* Define to 1 if your processor stores words with the most significant byte
+   first (like Motorola and SPARC, unlike Intel and VAX). */
+#undef WORDS_BIGENDIAN
 
 /* Define if arithmetic is subject to x87-style double rounding issue */
 #undef X87_DOUBLE_ROUNDING
 
+/* Define to 1 if on AIX 3.
+   System headers sometimes define this.
+   We just want to avoid a redefinition error message.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+
 /* Define on OpenBSD to activate all library features */
 #undef _BSD_SOURCE
 
@@ -1105,25 +1076,15 @@
 /* This must be defined on some systems to enable large file support. */
 #undef _LARGEFILE_SOURCE
 
-/* Define to 1 if on MINIX. */
-#undef _MINIX
-
 /* Define on NetBSD to activate all library features */
 #undef _NETBSD_SOURCE
 
 /* Define _OSF_SOURCE to get the makedev macro. */
 #undef _OSF_SOURCE
 
-/* Define to 2 if the system does not provide POSIX.1 features except with
-   this defined. */
-#undef _POSIX_1_SOURCE
-
 /* Define to activate features from IEEE Stds 1003.1-2001 */
 #undef _POSIX_C_SOURCE
 
-/* Define to 1 if you need to in order for `stat' and other things to work. */
-#undef _POSIX_SOURCE
-
 /* Define if you have POSIX threads, and your system does not define that. */
 #undef _POSIX_THREADS
 
@@ -1131,12 +1092,12 @@
 #undef _REENTRANT
 
 /* Define for Solaris 2.5.1 so the uint32_t typedef from <sys/synch.h>,
-   <pthread.h>, or <semaphore.h> is not used. If the typedef were allowed, the
+   <pthread.h>, or <semaphore.h> is not used. If the typedef was allowed, the
    #define below would cause a syntax error. */
 #undef _UINT32_T
 
 /* Define for Solaris 2.5.1 so the uint64_t typedef from <sys/synch.h>,
-   <pthread.h>, or <semaphore.h> is not used. If the typedef were allowed, the
+   <pthread.h>, or <semaphore.h> is not used. If the typedef was allowed, the
    #define below would cause a syntax error. */
 #undef _UINT64_T