diff --git a/configure b/configure
index 068bb33..8a23f2b 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in Revision: 85251 .
+# From configure.in Revision: 85351 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.65 for python 3.1.
 #
@@ -1923,11 +1923,11 @@
        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 $ac_includes_default
+	     enum { N = $2 / 2 - 1 };
 int
 main ()
 {
-static int test_array [1 - 2 * !(enum { N = $2 / 2 - 1 };
-	     0 < ($ac_type) ((((($ac_type) 1 << N) << N) - 1) * 2 + 1))];
+static int test_array [1 - 2 * !(0 < ($ac_type) ((((($ac_type) 1 << N) << N) - 1) * 2 + 1))];
 test_array [0] = 0
 
   ;
@@ -1938,11 +1938,11 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 $ac_includes_default
+	        enum { N = $2 / 2 - 1 };
 int
 main ()
 {
-static int test_array [1 - 2 * !(enum { N = $2 / 2 - 1 };
-		($ac_type) ((((($ac_type) 1 << N) << N) - 1) * 2 + 1)
+static int test_array [1 - 2 * !(($ac_type) ((((($ac_type) 1 << N) << N) - 1) * 2 + 1)
 		 < ($ac_type) ((((($ac_type) 1 << N) << N) - 1) * 2 + 2))];
 test_array [0] = 0
 
@@ -8041,6 +8041,8 @@
 # Check whether --with-system_ffi was given.
 if test "${with_system_ffi+set}" = set; then :
   withval=$with_system_ffi;
+else
+  with_system_ffi="no"
 fi
 
 
@@ -13920,8 +13922,8 @@
 
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 # Files that config.status was made for.
-config_files="`echo $ac_config_files`"
-config_headers="`echo $ac_config_headers`"
+config_files="$ac_config_files"
+config_headers="$ac_config_headers"
 
 _ACEOF
 
diff --git a/configure.in b/configure.in
index 2863b8d..15105e7 100644
--- a/configure.in
+++ b/configure.in
@@ -1995,7 +1995,9 @@
 # Check for use of the system libffi library
 AC_MSG_CHECKING(for --with-system-ffi)
 AC_ARG_WITH(system_ffi,
-            AC_HELP_STRING(--with-system-ffi, build _ctypes module using an installed ffi library))
+            AC_HELP_STRING(--with-system-ffi, build _ctypes module using an installed ffi library),
+            [],
+            [with_system_ffi="no"])
 
 AC_MSG_RESULT($with_system_ffi)
 
diff --git a/pyconfig.h.in b/pyconfig.h.in
index c057b32..4567823 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -33,7 +33,7 @@
 /* Define if --enable-ipv6 is specified */
 #undef ENABLE_IPV6
 
-/* Define if flock needs to be linked with bsd library */
+/* Define if flock needs to be linked with bsd library. */
 #undef FLOCK_NEEDS_LIBBSD
 
 /* Define if getpgrp() must be called as getpgrp(0). */
@@ -211,7 +211,7 @@
 /* Define to 1 if you have the `finite' function. */
 #undef HAVE_FINITE
 
-/* Define if you have the 'flock' function. */
+/* Define to 1 if you have the `flock' function. */
 #undef HAVE_FLOCK
 
 /* Define to 1 if you have the `fork' function. */