Dear all,

the attached patch adds stricter bounds-checking for DATA statements
with implied-do.  I chose to allow overindexing (for arrays of rank
greater than 1) for -std=legacy, as there might be codes in the wild
that need this (and this is accepted by some other compilers, while
NAG is strict here).  We now get a warning with -std=gnu, and an
error with -std=fxxxx.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

(The PR is over 15 years old, so no backport intended... ;-)

Thanks,
Harald