[PATCH] Make the path to etags used in the build system configurable [PR103021]

[Jeff Law]

On 11/28/2021 6:34 PM, Eric Gallager via Gcc-patches wrote:
> The attached patch allows users to specify a path to their `etags`
> executable for use when doing `make tags`, which is meant to close PR
> other/103021: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103021
> I based this patch off of this one from upstream automake:
> https://git.savannah.gnu.org/cgit/automake.git/commit/m4?id=d2ccbd7eb38d6a4277d6f42b994eb5a29b1edf29
> This means that I just supplied variables that the user can override
> for the tags programs, rather than having the configure scripts
> actually check for them. I handle etags and ctags separately because
> the intl subdirectory has separate targets for them. Tested with `make
> tags`; the changes I made work successfully, but some of the
> subdirectories still have broken tags targets, so I had to switch to
> `make -k tags` part way through. This isn't because of anything I did,
> though; the `-k` flag is only necessary because of errors that were
> already there before I touched anything. Also note that this patch
> only affects the subdirectories that use handwritten Makefiles; the
> ones that use automake will have to wait until we update the version
> of automake used to be 1.16.4 or newer before they'll be fixed.
OK for the trunk.
jeff