Mitigate Debian Trixie/Sid GCC/GNAT version mismatch

When I tested Debian Trixie, and Debian Sid, I saw that
GCC in PATH pointed to gcc-14, but gnat in path pointed
to GNAT-13, even if you manually install gnat-14.

GNAT 14 was marked experimental, but GCC 14 was marked
for use, in the apt repositories.

So this patch doesn't address the mismatch when doing e.g.
apt-get install gcc gnat

I will address the actual package dependency in a follow-up
patch, on the Debian dependencies config.

Signed-off-by: Leah Rowe <leah@libreboot.org>

script/trees

@@ -8,6 +8,7 @@ set -u -e
 
 . "include/lib.sh"
 . "include/git.sh"
+. "include/path.sh"
 
 XBMKPATH="$PATH"
 
@@ -205,6 +206,8 @@ check_cross_compiler()
 
 		xfix="${_xarch%-*}" && [ "$xfix" = "x86_64" ] && xfix="x64"
 
+		check_gnat_path
+
 		# sometimes buildgcc fails for like no reason. try twice.
 		make -C "$cbdir" crossgcc-$xfix $xgccargs || \
 		    make -C "$cbdir" crossgcc-$xfix $xgccargs || \