[Bug libfortran/67527] io.h sanitizer complains on 1 << 31

[zeccav at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67527

--- Comment #1 from Vittorio Zecca <zeccav at gmail dot com> ---
Same at line 383

#define IOPARM_DT_IONML_SET                     (1 << 31)

should be 

#define IOPARM_DT_IONML_SET                     (1u<< 31)