[gomp3] Handle tabs like spaces

[Tobias Burnus]

Jakub Jelinek wrote:
> Pedantically !$omp must be followed by space to be valid, but seems
> there are several OpenMP Fortran sources in the wild which use tabs.
> The following patch accepts them (gfc_gobble_whitespace will take
> care of pedantic warnings about tabs).


Old version: A warning is printed unconditionally and "!OMP$\t" lines 
are regarded as comment.

This patch: "!OMP$\t" is regarded as "!OMP$ " and no warning is ever 
printed.

Note: The warning does not seem to work for

!OMP$\tparallel

it only becomes active for

!OMP$\t\tparallel

I think one can change the behaviour to allow "!OMP$\t", but either by 
default or when using -pedantic a warning should be printed.

Tobias