parser: Fix single-quoted patterns in here-documents

The script

	x=*
	cat <<- EOF
		${x#'*'}
	EOF

prints * instead of nothing as it should.  The problem is that
when we're in sqsyntax context in a here-document, we won't add
CTLESC as we should.  This patch fixes it:

Reported-by: Harald van Dijk <harald@gigawatt.nl>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

src/parser.c

@@ -934,7 +934,8 @@ readtoken1(int firstc, char const *syntax, char *eofmark, int striptabs)
 				USTPUTC(c, out);
 				break;
 			case CCTL:
-				if (eofmark == NULL || synstack->dblquote)
+				if ((!eofmark) | synstack->dblquote |
+				    synstack->varnest)
 					USTPUTC(CTLESC, out);
 				USTPUTC(c, out);
 				break;