This patch extends PC/config.h and configure.in as appropriate for
64-bit readiness (the config values are needed for patches that I will
be submitting later today. The changes are as follows:

- add SIZEOF_OFF_T #define's to PC/config.h (it was already in configure.in)

- add SIZEOF_TIME_T #define to PC/config.h and configure
Needed for some buffer overflow checking because sizeof(time_t) is
different on Win64.

- add SIZEOF_FPOS_T #define
Needed for the Win64 large file support implementation.

- add SIZEOF_HKEY in PC/config.h only
Needed for proper Win32 vs. Win64 handling in PC/winreg.c

- #define HAVE_LARGEFILE_SUPPORT for Win64

- typedef long intptr_t; for all Windows except Win64 (which defines it
itself)
This is a new ANSI (I think) type that is useful (and used by me) for
proper handling in msvcrtmodule.c and posixmodule.c

- indent the nested #ifdef's and #defines in PC/config.h
This is *so* much more readable. There cannot be a compiler
compatibilty issue here can there? Perl uses indented #defines and it
compiles with everything.
diff --git a/config.h.in b/config.h.in
index 704f50a..89e52a2 100644
--- a/config.h.in
+++ b/config.h.in
@@ -213,6 +213,9 @@
 /* The number of bytes in an off_t. */
 #undef SIZEOF_OFF_T
 
+/* The number of bytes in a time_t. */
+#undef SIZEOF_TIME_T
+
 /* Defined to enable large file support when an off_t is bigger than a long
    and long long is available and at least as big as an off_t. You may need
    to add some flags for configuration and compilation to enable this mode.
@@ -234,6 +237,9 @@
 /* The number of bytes in a float.  */
 #undef SIZEOF_FLOAT
 
+/* The number of bytes in a fpos_t.  */
+#undef SIZEOF_FPOS_T
+
 /* The number of bytes in a int.  */
 #undef SIZEOF_INT
 
@@ -546,6 +552,9 @@
 /* Define if you have the <sys/socket.h> header file.  */
 #undef HAVE_SYS_SOCKET_H
 
+/* Define if you have the <sys/socket.h> header file.  */
+#undef HAVE_SYS_SOCKET_H
+
 /* Define if you have the <sys/time.h> header file.  */
 #undef HAVE_SYS_TIME_H