bin/package: exit with nonzero status on build failure

Build scripts and the like ought to be able to check the results of
the build using the exit status of the build command.

bin/package,
src/cmd/INIT/package.sh:
- Add global error_status variable to keep track of the highest
  exit status of all commands using capture(). Exit with that.
- capture():
  * When capturing build output using 'tee', change the regular
    pipe construct (which doesn't preserve the exit status of pipe
    elements except the last one) to a couple of background jobs
    connected with a FIFO (named pipe). This allows getting the
    build's exit status using the "wait" command.
  * Update error_status on every invocation of capture().

(cherry picked from commit 22c3a6e1b32f3ab7eeca45adb76863982dc3e334)

bin/package

@@ -3966,13 +3966,18 @@ capture() # file command ...
 		0)	if	executable ! $TEE
 			then	TEE=tee
 			fi
+			rm -f $o.fifo
+			mkfifo -m 600 $o.fifo || exit
+			$TEE -a $o < $o.fifo &
 			{
 				case $s in
 				?*)	echo "$s"  ;;
 				esac
 				showenv $action
 				"$@"
-			} < /dev/null 2>&1 | $TEE -a $o
+			} > $o.fifo 2>&1 &
+			rm $o.fifo 	# unlink early
+			wait "$!"	# get build's exit status
 			;;
 		*)	{
 				case $s in
@@ -3987,6 +3992,10 @@ capture() # file command ...
 	*)	$make "$@"
 		;;
 	esac
+	exit_status=$?
+	if	test "$exit_status" -gt "$error_status"
+	then	error_status=$exit_status
+	fi
 }
 
 package_install() # dest sum
@@ -4358,6 +4367,8 @@ isascii()
 	return $__isascii__
 }
 
+error_status=0
+
 case $action in
 
 admin)	while	test ! -f $admin_db
@@ -7358,3 +7369,5 @@ TEST)	set '' $target $package
 	;;
 
 esac
+
+exit "$error_status"

src/cmd/INIT/package.sh

@@ -3965,13 +3965,18 @@ capture() # file command ...
 		0)	if	executable ! $TEE
 			then	TEE=tee
 			fi
+			rm -f $o.fifo
+			mkfifo -m 600 $o.fifo || exit
+			$TEE -a $o < $o.fifo &
 			{
 				case $s in
 				?*)	echo "$s"  ;;
 				esac
 				showenv $action
 				"$@"
-			} < /dev/null 2>&1 | $TEE -a $o
+			} > $o.fifo 2>&1 &
+			rm $o.fifo 	# unlink early
+			wait "$!"	# get build's exit status
 			;;
 		*)	{
 				case $s in
@@ -3986,6 +3991,10 @@ capture() # file command ...
 	*)	$make "$@"
 		;;
 	esac
+	exit_status=$?
+	if	test "$exit_status" -gt "$error_status"
+	then	error_status=$exit_status
+	fi
 }
 
 package_install() # dest sum
@@ -4357,6 +4366,8 @@ isascii()
 	return $__isascii__
 }
 
+error_status=0
+
 case $action in
 
 admin)	while	test ! -f $admin_db
@@ -7357,3 +7368,5 @@ TEST)	set '' $target $package
 	;;
 
 esac
+
+exit "$error_status"