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>

.gitignore

@@ -41,3 +41,4 @@
 /f
 /r
 /e
+/xbmkpath/

include/lib.sh

@@ -95,6 +95,9 @@ if [ -z "${TMPDIR+x}" ]; then
 	export TMPDIR="/tmp"
 	export TMPDIR="$(mktemp -d -t xbmk_XXXXXXXX)"
 	touch lock || $err "cannot create 'lock' file"
+	rm -Rf xbmkpath || $err "cannot create xbmkpath"
+	mkdir -p xbmkpath || $err "cannot create xbmkpath"
+	export PATH="$PWD/xbmkpath:$PATH" || $err "Can't create xbmkpath"
 	xbmk_parent="y"
 fi
 

include/path.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env sh
+# SPDX-License-Identifier: MIT
+# Copyright (c) 2024 Leah Rowe <leah@libreboot.org>
+
+# debian trixie/sid ship with gcc 14 when running "gcc",
+# but (as of December 2024) gnat is gnat-13. we must create
+# a symlink accordingly.
+# however, the user may also have gcc 13+14, but only gnat 13
+check_gnat_path()
+{
+	eval `setvars "" gccver gnatver gccdir`
+	command -v gcc 1>/dev/null || $err "Command 'gcc' unavailable."
+
+	for _util in gcc gnat; do
+		eval "$_util --version 1>/dev/null 2>/dev/null || continue"
+		eval "${_util}ver=\"`$_util --version 2>/dev/null | head -n1`\""
+		eval "${_util}ver=\"\${${_util}ver##* }\""
+		eval "${_util}ver=\"\${${_util}ver%%.*}\""
+	done
+
+	[ -z "$gccver" ] && $err "Cannot detect host GCC version"
+	[ "$gnatver" = "$gccver" ] && return 0
+
+	gccdir="$(dirname "$(command -v gcc)")"
+
+	for _gnatbin in "$gccdir/gnat-"*; do
+		[ -f "$_gnatbin" ] || continue
+		[ "${_gnatbin#"$gccdir/gnat-"}" = "$gccver" ] || continue
+		gnatver="${_gnatbin#"$gccdir/gnat-"}"
+		break
+	done
+
+	[ "$gnatver" = "$gccver" ] || $err "GCC/GNAT versions do not match."
+
+	# we already established that the versions match, but if gnat isn't
+	# in path, then we assume it's in e.g. /usr/bin/gnat-14
+	(
+	x_ cd xbmkpath
+	for _gnatbin in "$gccdir/gnat"*"-$gccver"; do
+		[ -e "$_gnatbin" ] || continue
+		_gnatutil="${_gnatbin##*/}"
+		ln -s "$_gnatbin" "${_gnatutil%"-$gccver"}" || \
+		    $err "E: ln -s \"$_gnatbin\" \"${_gnatutil%"-$gccver"}\""
+	done
+	) || $err "Cannot create gnat-$gccver link in $gccdir"
+}

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 || \