[Bug fortran/58001] Make it possible to silence "Extension: Tab character in format" warning

[dominiq at lps dot ens.fr]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58001

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Created attachment 30573
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30573&action=edit
test case with tabs