fix comsub inside parameter expansion in here-document; fix readline longjmp botch; posix change for unset non-identifier; posix change for double quotes inside backquote comsub in here-document; add missing posix pieces to umask builtin

tests/comsub.tests

@@ -76,6 +76,11 @@ echo $(echo $( echo nested )
 )
 )
 
+BUILDDIR=/builds/test
+read << EOC
+Dir: ${BUILDDIR#<(echo a)/}
+EOC
+
 ${THIS_SH} ./comsub1.sub
 ${THIS_SH} ./comsub2.sub
 ${THIS_SH} ./comsub3.sub