Python no longer compiled on Windows, due to #include file confusion

over SEP, ALTSEP and MAXPATHLEN.
Patched up posixmodule.c for MSVC, but unsure what the story is now on
other non-Unixish platforms -- the preprocessor maze has no exit <wink>.

Modules/posixmodule.c

@@ -193,10 +193,6 @@ extern int lstat(const char *, struct stat *);
 #include <sys/utsname.h>
 #endif /* HAVE_SYS_UTSNAME_H */
 
-#ifndef MAXPATHLEN
-#define MAXPATHLEN 1024
-#endif /* MAXPATHLEN */
-
 #ifdef HAVE_DIRENT_H
 #include <dirent.h>
 #define NAMLEN(dirent) strlen((dirent)->d_name)
@@ -223,6 +219,7 @@ extern int lstat(const char *, struct stat *);
 #include <direct.h>
 #include <io.h>
 #include <process.h>
+#include "osdefs.h"
 #define WINDOWS_LEAN_AND_MEAN
 #include <windows.h>
 #ifdef MS_WIN32
@@ -238,6 +235,10 @@ extern int lstat(const char *, struct stat *);
 #include <io.h>
 #endif /* OS2 */
 
+#ifndef MAXPATHLEN
+#define MAXPATHLEN 1024
+#endif /* MAXPATHLEN */
+
 #ifdef UNION_WAIT
 /* Emulate some macros on systems that have a union instead of macros */