Libgpr fails to compile with FSF GNAT

[A-Yerkesh]

Hi!

I ran into the problem that Alire's Libgpr doesn't compile with FSF GNAT. Here is the error:

gpr-compilation-process.adb:44:29: error: operator for type "String" is not declared in "Env_Maps"

Looking at master, i see that this bug was fixed, but Libgpr crate in Alire was never updated.

This is how gpr-compilation-process.adb:44 looks on master branch of this project:

(String, Env_Maps.Map, "<", Env_Maps."=");

And this is how it looks in Alire's version:

(String, Env_Maps.Map, Env_Maps."<", Env_Maps."=");

Could you please update the Libgpr crate to reflect the current state of Gpr?

Thanks!