Make sure to have full configuration info in sys/_types.h.

Make sure to have full configuration info in sys/_types.h.

The following testcase:

  $ cat > test.c <<EOF
  #include <sys/select.h>
  #include <sys/time.h>
  EOF
  $ gcc -c test.c

emits the following error:

  /usr/include/sys/reent.h:276:3: error: expected specifier-qualifier-list befor
e ‘_fpos64_t’
     _fpos64_t _EXFNPTR(_seek64, (struct _reent *, _PTR, _fpos64_t, int));
     ^

The reason is that the load order from sys/select.h includes sys/_types.h
before sys/config.h has been included from anywhere else.  sys/_types.h
defines _fpos64_t only if __LARGE64_FILES is defined, but it never is in
this scenario.  So sys/_types.h has to make sure to get the configuration
info by itself.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>