Add -a/--all option to brl which

Prints the list of strata in which the given binary can be found.

src/slash-bedrock/libexec/brl-which

@@ -21,6 +21,7 @@ Options:
   ${color_sub}<none>          ${color_norm}guess type from identifier
   ${color_cmd}-c${color_norm}, ${color_cmd}--current   ${color_norm}which ${color_term}stratum${color_norm} provides current process
   ${color_cmd}-b${color_norm}, ${color_cmd}--bin       ${color_norm}which ${color_term}stratum${color_norm} provides a given binary in \$PATH
+  ${color_cmd}-a${color_norm}, ${color_cmd}--all       ${color_norm}which ${color_term}strata${color_norm} provide a given binary in \$PATH
   ${color_cmd}-f${color_norm}, ${color_cmd}--file      ${color_norm}which ${color_term}stratum${color_norm} provides a given file path
   ${color_cmd}-p${color_norm}, ${color_cmd}--pid       ${color_norm}which ${color_term}stratum${color_norm} provides a given process ID
   ${color_cmd}-x${color_norm}, ${color_cmd}--xwindow   ${color_norm}which ${color_term}stratum${color_norm} provides a given X11 window (requires xprop)
@@ -67,6 +68,32 @@ which_bin() {
 	done
 }
 
+which_bin_all() (
+	IFS=':'
+	while [ -n "${1:-}" ]; do
+		for strat_dir in /bedrock/strata/*; do
+			if [ ! -d "${strat_dir}" ] || [ -h "${strat_dir}" ]; then
+				continue
+			fi
+
+			for dir in ${PATH}; do
+				case "${dir}" in
+				''|'.'|/bedrock/*)
+					continue
+					;;
+				esac
+
+				if [ -e "${strat_dir}/${dir}/${1}" ]; then
+					which_file "${strat_dir}/${dir}/${1}"
+					break
+				fi
+			done
+		done
+
+		shift
+	done
+)
+
 which_file() {
 	while [ -n "${1:-}" ]; do
 		if ! [ -e "${1}" ]; then
@@ -146,6 +173,10 @@ case "${1:-}" in
 	shift
 	which_bin "${@}"
 	;;
+"-a" | "--all")
+	shift
+	which_bin_all "${@}"
+	;;
 "-f" | "--file")
 	shift
 	which_file "${@}"