merge from base, from sashan@:

> - odd condition/test in PF lexer
> (and other lexers too)
>
> This commit rectifies earlier change:
>
> in the lex... even inside quotes, a \ followed by space or tab should
> expand to space or tab, and a \ followed by newline should be ignored
> (as a line continuation).  compatible with the needs of hoststated
> (which has the most strict quoted string requirements), and ifstated
> (where one commonly does line continuations in strings).
>
> OK deraadt@, OK millert@

parse.y

@@ -467,7 +467,8 @@ yylex(void)
 			} else if (c == '\\') {
 				if ((next = lgetc(quotec)) == EOF)
 					return (0);
-				if (next == quotec || c == ' ' || c == '\t')
+				if (next == quotec || next == ' ' ||
+				    next == '\t')
 					c = next;
 				else if (next == '\n') {
 					file->lineno++;