bug#30086: Please add a flag to stop etags from falling back to Fortran and C

["Francesco Potortì" <pot@gnu.org>]

>Previous discussion here: 
>http://lists.gnu.org/archive/html/emacs-devel/2018-01/msg00323.html

I argue that fallbacks should be removed, or at least the default
reversed, i.e., not use fallback unless some --legacy-fallback option is
given.

Falbacks only make sense in an environment where Fortran and C are much
more prominently used than other languages AND where it is common to use
nonstandard suffixes for the source files.

Neither assumption is true nowadays, and I'd say it hasn't been true for
projects started in maybe the latest 20 years, while it may have been
true for legacy projects at the time when Etags was written.

Those legacy projects are the only reason why Etags should keep using a
default.  I assume that if people need to support Fortran or C
environments 20 years old without even changing the file name suffixes,
they are probably forced to use old tools, among which old Etag
versions, and we should not worry about such strict compatibility.

So, I'd say, just remove fallbacks, or use them only if a
--legacy-fallback option is used.