[Bug libfortran/66936] io/unix.c gratuitously uses S_IRWXG and S_IRWXO on the basis that mkstemp() is available

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66936

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
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           Priority|P3                          |P5
           Severity|normal                      |enhancement