Like config.h.in but in Ada

[Victor Porton]

I want to create file config.ads similar to config.h but with Ada
syntax instead of C.

I created config.ads.in, added it to configure.ac and got:

package Boiler.Config is
   Data_Dir: constant String := "${prefix}/share";
end Boiler.Config;

from

package Boiler.Config is
   Data_Dir: constant String := "@datadir@";
end Boiler.Config;

It is not acceptable because Ada does not understand ${prefix}.

How to make a value into an Ada string (a string delimited by double
quotes)?

It could be not ideal but acceptable if the code didn't work with paths
containing double quotes.