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/configure.in b/configure.in
index fd5f368..5790801 100644
--- a/configure.in
+++ b/configure.in
@@ -389,6 +389,7 @@
 AC_CHECK_SIZEOF(short)
 AC_CHECK_SIZEOF(float)
 AC_CHECK_SIZEOF(double)
+AC_CHECK_SIZEOF(fpos_t)
 
 AC_MSG_CHECKING(for long long support)
 have_long_long=no
@@ -424,6 +425,22 @@
   AC_MSG_RESULT(no)
 fi
 
+# AC_CHECK_SIZEOF() doesn't include <time.h>.
+AC_MSG_CHECKING(size of time_t)
+AC_CACHE_VAL(ac_cv_sizeof_time_t,
+[AC_TRY_RUN([#include <stdio.h>
+#include <time.h>
+main()
+{
+  FILE *f=fopen("conftestval", "w");
+  if (!f) exit(1);
+  fprintf(f, "%d\n", sizeof(time_t));
+  exit(0);
+}], ac_cv_sizeof_time_t=`cat conftestval`, ac_cv_sizeof_time_t=0)
+])
+AC_MSG_RESULT($ac_cv_sizeof_time_t)
+AC_DEFINE_UNQUOTED(SIZEOF_TIME_T, $ac_cv_sizeof_time_t)
+
 
 # Minor variations in building a framework between NextStep versions 4 and 5
 AC_SUBST(LIBTOOL_CRUFT)