sh: Make double-quotes quote a '}' inside ${v#...} and ${v%...}.

Exp-run done by:	pav (with some other sh(1) changes)
PR:			bin/57554

bin/sh/parser.c

@@ -1234,7 +1234,8 @@ readtoken1(int firstc, char const *initialsyntax, char *eofmark, int striptabs)
 			case CENDVAR:	/* '}' */
 				if (level > 0 &&
 				    (state[level].category == TSTATE_VAR_OLD ||
-				    state[level].category == TSTATE_VAR_NEW)) {
+				    (state[level].category == TSTATE_VAR_NEW &&
+				     state[level].syntax == BASESYNTAX))) {
 					if (state[level].category == TSTATE_VAR_OLD)
 						state[level - 1].syntax = state[level].syntax;
 					else

tools/regression/bin/sh/expansion/trim5.0

@@ -0,0 +1,28 @@
+# $FreeBSD$
+
+e= q='?' a='*' t=texttext s='ast*que?non' p='/et[c]/' w='a b c' b='{{(#)}}'
+h='##'
+failures=''
+ok=''
+
+testcase() {
+	code="$1"
+	expected="$2"
+	oIFS="$IFS"
+	eval "$code"
+	IFS='|'
+	result="$#|$*"
+	IFS="$oIFS"
+	if [ "x$result" = "x$expected" ]; then
+		ok=x$ok
+	else
+		failures=x$failures
+		echo "For $code, expected $expected actual $result"
+	fi
+}
+
+testcase 'set -- "${b%'\'}\''}"'		'1|{{(#)}'
+testcase 'set -- ${b%"}"}'			'1|{{(#)}'
+testcase 'set -- "${b%"}"}"'			'1|{{(#)}'
+
+test "x$failures" = x