[277823 ] devel/matreshka: Build fails in package phase

Hello,

Regarding the mentioned Port, and Problem Report[1], Matreshka currently
installs shared libraries with the compiler version hard-coded in the
filename, example:

lib/matreshka/xml/libmatreshka-xml-12.2.so.20.0

The 12.2 in the above corresponds to the Free Software Foundation's Ada
compiler, GNAT-12. Currently I am testing the following addition to the
Makefile:

> PLIST_SUB=GNAT_VERSION=         ${_GNAT_VERSION}
> [...]
> _GNAT_VERSION=                  12.3

And have made the required changes to the pkg-plist, that is, replacing
all occurences of "12.2" with %%GNAT_VERSION%%, however, I am left
wondering if there is another way to obtain the version of GCC used,
instead of volunteers hard coding the version manually in the Makefile,
every time the tool chain is updated...

Summary:
How can I get the version number of the tool chain used to compile a
Port?

1: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=277823

Thanks,
Alastair