PR libfortran/90274
* io/format.c (parse_format_list): Implement the E0 exponent
width to provide smallest possible width for exponent fields.
Refactor code for correct parsing and better readability of the
code.
* io/io.h (write_real_w0): Change interface to pass in pointer
to fnode.
* io/transfer.c: Update all calls to write_real_w0 to use the
new interface.
* io/write.c ((write_real_w0): Use the new interface with fnode
to access both the decimal precision and exponent widths used in
build_float_string.
* io/write_float.def (build_float_string): Use the passed in
exponent width to calculate the used width in the case of E0.
From-SVN: r279828
2b70275ee1