[Bug ada/64492] Disabling libada prevents building gnattools-cross

["laguest at archeia dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64492

--- Comment #14 from Luke A. Guest <laguest at archeia dot com> ---
(In reply to simon from comment #13)

> TOOLS_TARGET_PAIRS is set in both gnattools/Makefile (when it has been
> configured) and gcc/ada/gcc-interface/Makefile.in. Your patch is to the
> gnattools/ one, the gcc-interface one already has this pair.

Yup, as with the patches that we've wrangling with for the past 15 years (yes,
that long) that has been the case, although I don't know when it all got split
up into libada and gnattools dirs. But, the gnattool/configure case was moved
there from the gcc-interface/Makefile.in, I always thought that they just
forgot to remove the one from there. 

> If it is the case that any arm-*-eabi target is going to be a bare runtime

If any *-elf/eabi-elf/coff/whatever target is going to be bare runtime...

When I first started looking into this I was interested in ARM, not so much
now. But maybe in the future.

> target, with --disable-libada disabling gnattools/, then Ericâs patch and
> Arnoâs incantation will IMO work - I just built GCC 5 arm-eabi with Ericâs
> patch and the two files were successfully copied into build/gcc/ada/tools,
> and arm-eabi-gnatmake is capable of building a library. Havenât checked the

Interesting.

> map feature yet.

The what?

> Looking at the two versions of TOOLS_TARGET_PAIRS, it seems that
> gcc-interface/Makefile is mainly concerned with building the RTS
> (LIBGNAT_TARGET_PAIRS etc) with the TOOLS_TARGET_PAIRS being left in place,
> pretty much as fossils, when building the tools was moved to
> gnattools/Makefile.

Would be nice if this was documented in an easy to understand way in the
makefiles, as in "What it's there for and why."

As I state above, I have been dabbling on and off for 14 years for this. I have
posted about it in various places and only got the response of the incantation,
which I told them never worked, shame it's taken this long to get this quite
major issue fixed.