bug#43742: Unable to compile ada-mode

[Colton Lewis via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

On Thursday, October 8, 2020 10:43:07 AM CDT Stephen Leake wrote:
> 
> > On a tangent, the online Emacs manual
> 
> Where?

First result on google for the string "emacs ada-mode".
First sentence under Installation section.

https://www.gnu.org/software/emacs/manual/html_mono/ada-mode.html#Installation

> >    [Ada]          wisi-ada.adb
> >    [Ada]          wisitoken.adb
> > sal-gen_unbounded_definite_red_black_trees.adb:308:26: access
> > discriminant in return aggregate would be a dangling reference
> 
> That's a new instance of a known bug; see the WORKAROUND note at line
> 321 in that file; delete the '.all' and it magically works.
Deleted ".all" everywhere the compiler complained. More errors.

wisitoken.ads:80:04: instantiation error at sal-gen_definite_doubly_linked_lists.adb:268
wisitoken.ads:80:04: instantiation error at sal-gen_unbounded_definite_queues.ads:88
wisitoken.ads:80:04: access discriminant in return aggregate would be a dangling reference
wisi.ads:497:04: instantiation error at sal-gen_unbounded_definite_red_black_trees.adb:308
wisi.ads:497:04: access discriminant in return aggregate would be a dangling reference

> 
> > clang-10: warning: argument unused during compilation:
> > '-specs=/tmp/GNAT-TEMP-000014.TMP' [-Wunused-command-line-argument]
> 
> This I don't understand

gprbuild grabs the first C compiler it can find on the system. I have
clang installed, so it uses that as the C compiler. Clang doesn't support
a "-spec" argument. 

https://docs.adacore.com/gprbuild-docs/html/gprbuild_ug/companion_tools.html

Might want to add
for Driver ("C") use "gcc";
somewhere.