makepkg: exit via default signal handler in trap_exit

Similar to how we manage receipt of SIGINT in pacman's internal
downloader, catch the signal and invoke our own trap handler before
unsetting it and calling the default. This requires a slight
modification to the arguments passed to trap_exit so we can pass the
raised signal to trap_exit (note that we substitue USR1 for ERR since
the latter is unique to bash).

Fixes FS#28491.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>

scripts/makepkg.sh.in

@@ -118,12 +118,17 @@ error() {
 # the fakeroot call, the error message will be printed by the main call.
 ##
 trap_exit() {
+	local signal=$1; shift
+
 	if (( ! INFAKEROOT )); then
 		echo
 		error "$@"
 	fi
 	[[ -n $srclinks ]] && rm -rf "$srclinks"
-	exit 1
+
+	# unset the trap for this signal, and then call the default handler
+	trap -- "$signal"
+	kill "-$signal" "$$"
 }
 
 
@@ -1964,10 +1969,10 @@ done
 # setup signal traps
 trap 'clean_up' 0
 for signal in TERM HUP QUIT; do
-	trap "trap_exit \"$(gettext "%s signal caught. Exiting...")\" \"$signal\"" "$signal"
+	trap "trap_exit $signal \"$(gettext "%s signal caught. Exiting...")\" \"$signal\"" "$signal"
 done
-trap 'trap_exit "$(gettext "Aborted by user! Exiting...")"' INT
-trap 'trap_exit "$(gettext "An unknown error has occurred. Exiting...")"' ERR
+trap 'trap_exit INT "$(gettext "Aborted by user! Exiting...")"' INT
+trap 'trap_exit USR1 "$(gettext "An unknown error has occurred. Exiting...")"' ERR
 set -E
 
 # preserve environment variables and canonicalize path