armbian-next: bring find_toolchain() back from the dead; force SKIP_EXTERNAL_TOOLCHAINS=no to force use external toolchains

- handle a lot of corner cases, some toolchains are i386-only and won't run on modern x64 systems

lib/functions/compilation/utils-compilation.sh

@@ -43,34 +43,79 @@ find_toolchain() {
 		echo "/usr/bin"
 		return
 	}
+
 	local compiler=$1
 	local expression=$2
 	local dist=10
+
+	display_alert "SKIP_EXTERNAL_TOOLCHAINS=no, Searching for toolchain" "'${compiler}' '${expression}'" "warn"
+
 	local toolchain=""
+
 	# extract target major.minor version from expression
 	local target_ver
 	target_ver=$(grep -oE "[[:digit:]]+\.[[:digit:]]" <<< "$expression")
+	display_alert "Searching for toolchain" "'${compiler}' '${expression}': target_ver: '${target_ver}'" "debug"
+
 	for dir in "${SRC}"/cache/toolchain/*/; do
+		display_alert "Checking toolchain" "${dir}" "debug"
+		local gcc_bin="${dir}bin/${compiler}gcc"
 		# check if is a toolchain for current $ARCH
-		[[ ! -f ${dir}bin/${compiler}gcc ]] && continue
+		if [[ ! -f "${gcc_bin}" ]]; then
+			display_alert "Can't find compiler" "'${dir}' :: '${gcc_bin}" "debug"
+			continue
+		else
+			display_alert "Found compiler" "'${dir}' :: '${gcc_bin}" "debug"
+		fi
+
+		declare gcc_bin_info
+		gcc_bin_info="$(file "${gcc_bin}" || true)"
+
+		display_alert "Testing toolchain" "'${gcc_bin}': '${gcc_bin_info}'" "debug"
+
 		# get toolchain major.minor version
-		local gcc_ver
+		declare gcc_ver_simple
-		gcc_ver=$("${dir}bin/${compiler}gcc" -dumpversion | grep -oE "^[[:digit:]]+\.[[:digit:]]")
+		gcc_ver_simple="$("${gcc_bin}" -dumpversion 2>&1 || true)" # this might fail: toolchain can't run on current host
+
+		display_alert "Checking version" "'${gcc_ver_simple}' for '${gcc_bin}'" "debug"
+		if [[ "x${gcc_ver_simple}x" == "xx" ]]; then
+			display_alert "Can't obtain version" "'${gcc_bin}' for '${gcc_bin}': '${gcc_ver_simple}'" "debug"
+			continue
+		fi
+
+		declare gcc_ver
+		gcc_ver="$(echo "${gcc_ver_simple}" | grep -oE "^[[:digit:]]+\.[[:digit:]]" || true)" # this might fail to parse
+		if [[ "x${gcc_ver}x" == "xx" ]]; then
+			display_alert "Can't parse version" "'${gcc_bin}' for '${gcc_bin}': '${gcc_ver_simple}': '${gcc_ver}'" "debug"
+			continue
+		fi
+
+		display_alert "Found working toolchain" "'${gcc_bin}' gcc_ver_simple:'${gcc_ver_simple}' gcc_ver:'${gcc_ver}'" "debug"
+
 		# check if toolchain version satisfies requirement
-		awk "BEGIN{exit ! ($gcc_ver $expression)}" > /dev/null || continue
+		if ! awk "BEGIN{exit ! ($gcc_ver $expression)}" > /dev/null; then
+			display_alert "Toolchain version" "'${gcc_bin}' '${gcc_ver}' doesn't satisfy '${expression}'" "debug"
+			continue
+		fi
+
 		# check if found version is the closest to target
 		# may need different logic here with more than 1 digit minor version numbers
 		# numbers: 3.9 > 3.10; versions: 3.9 < 3.10
 		# dpkg --compare-versions can be used here if operators are changed
-		local d
+		declare d
 		d=$(awk '{x = $1 - $2}{printf "%.1f\n", (x > 0) ? x : -x}' <<< "$target_ver $gcc_ver")
 		if awk "BEGIN{exit ! ($d < $dist)}" > /dev/null; then
-			dist=$d
+			dist="$d"
-			toolchain=${dir}bin
+			toolchain="${dir}bin"
+			display_alert "Found toolchain" "'${gcc_bin}' ver:'${gcc_ver}' expression:'${expression}' dist:'${dist}'" "debug"
 		fi
 	done
+
+	display_alert "Using toolchain" "${toolchain}" "info"
+
 	echo "$toolchain"
 }
+
 # overlayfs_wrapper <operation> <workdir> <description>
 #
 # <operation>: wrap|cleanup