build-system: use readarray to set list Systems from YAML config

CHANGELOG.md

@@ -10,7 +10,7 @@
 * BUGFIX: group dependencies specified with the option '--with' were ignored
   (issue #236)
 * BUGFIX: writing list of 'systems' to module configuration file fixed
-  (issue #235)
+  (issues #235, #243)
 * CHANGE: files in `$PMODULES_TMPDIR/<module>` are now removed before
   and after building a module (except cleanup has been disbaled).
   (issue #242)

Pmodules/libpbuild.bash

@@ -897,9 +897,9 @@ declare -a Systems
 pbuild.build_module_yaml(){
 	local -- module_name="$1"
 	local -- module_version="$2"
-	Config=$3
+	Config="$3"
 	local -- module_relstage="${Config['relstage']}"
-	Systems=( ${Config['systems']} )
+	readarray -t Systems <<< "${Config['systems']}"
 	shift 3
 	_build_module "${module_name}" "${module_version}" "${module_relstage}" "$@"
 }