diff --git a/sunrise-commit b/sunrise-commit
index 7128ec1..17377fa 100755
--- a/sunrise-commit
+++ b/sunrise-commit
@@ -26,6 +26,16 @@ req() {
 	"${@}" || die "'${@}' failed."
 }
 
+# Append the arguments to an IFS-separated list variable whose name was
+# passed as the first arg.
+array_append() {
+	local varname
+	varname=${1}
+	shift
+
+	eval "set -- \${${varname}} \"\${@}\"; ${varname}=\${*}"
+}
+
 # -- POSIX compat --
 
 # Check whether 'local' is supported.
@@ -97,7 +107,7 @@ is_package_removal() {
 	local dir olist
 	for dir in ${list}; do
 		# 2) These removes have to remove whole directories.
-		is_whole_dir_removed ${dir} && olist=${olist+${olist} }${dir}
+		is_whole_dir_removed ${dir} && array_append olist "${dir}"
 	done
 
 	[ -z "${olist}" ] && return 1
@@ -142,7 +152,7 @@ find_ebuilds() {
 				esac
 			fi
 			SC_CP=${SC_CP:+${SC_CP}, }${category}${pkg}
-			SC_REMOVED_PACKAGE_LIST=${SC_REMOVED_PACKAGE_LIST:+${SC_REMOVED_PACKAGE_LIST} }${category}${pkg}
+			array_append SC_REMOVED_PACKAGE_LIST "${category}${pkg}"
 		done
 
 		SC_ROOT=${category:+../}
@@ -151,7 +161,7 @@ find_ebuilds() {
 		# relative to SC_ROOT.
 		SC_CHANGE_LIST=
 		for pkg in ${SC_REMOVED_PACKAGE_LIST}; do
-			SC_CHANGE_LIST=${SC_CHANGE_LIST+${SC_CHANGE_LIST} }${SC_ROOT}${pkg}
+			array_append SC_CHANGE_LIST "${SC_ROOT}${pkg}"
 		done
 
 		local sdir
@@ -324,14 +334,14 @@ main() {
 
 			--)
 				shift
-				commitmsg=${commitmsg+${commitmsg} }${@}
+				array_append commitmsg "${@}"
 				break
 				;;
 			-*)
 				die "Unknown option: ${1}; see --help." >&2
 				;;
 			*)
-				commitmsg=${commitmsg+${commitmsg} }${1}
+				array_append commitmsg "${1}"
 				;;
 		esac
 		shift
@@ -464,7 +474,7 @@ main() {
 			local pkg regex
 			regex=
 			for pkg in ${SC_REMOVED_PACKAGE_LIST}; do
-				regex="${regex:+${regex}\|}${pkg}"
+				regex=${regex:+${regex}\|}${pkg}
 			done
 
 			say "${GREEN}Grepping for package references...${RESET}"