unconditionally define PGRP_PIPE; fix wait in funsubs; fix REPLY as nameref in varsub; fix crash with parse errors in compound assignments

tests/parser.right

@@ -1,3 +1,4 @@
+bash: -c: line 1: unexpected EOF while looking for matching `)'
 AAA
 bash5: line 1: `invalid-name': not a valid identifier
 in

tests/parser.tests

@@ -7,6 +7,9 @@ case x in x) if ((1)); then :; fi esac
 case x in x) if ((true ) ); then :; fi ;; esac
 case x in x) if ((true ) ); then :; fi esac
 
+# problem with bash-5.2
+${THIS_SH} -c '((X=([))]' bash
+
 # this has to be in a separate file to get desired EOF behavior
 ${THIS_SH} ./parser1.sub