Use NAMEDATALEN instead of local define.

Modify path separators for Win32.

Per ideas from Takahiro Itagaki

contrib/pg_upgrade/file.c

@@ -13,12 +13,6 @@
 #include <windows.h>
 #endif
 
-#ifndef WIN32
-char		pathSeparator = '/';
-#else
-char		pathSeparator = '\\';
-#endif
-
 
 static int	copy_file(const char *fromfile, const char *tofile, bool force);