[xml] Little bug in UnaryExpr

["Tom ." <ptittom free fr>]

Hi,
libxml rejects expressions such as '- - 17' whereas the XPath Rec says they
are valid expressions:
[27]  UnaryExpr     ::= UnionExpr
                        | '-' UnaryExpr

The attached patch should fix the problem (2 minor changes in
xmlXPathEvalUnaryExpr, not tested).

Tom.

--- src/xpath.c	Mon Mar 12 18:46:41 2001
+++ dev/xpath.c	Mon Mar 12 18:49:10 2001
@@ -5630,8 +5630,8 @@
     int minus = 0;
 
     SKIP_BLANKS;
-    if (CUR == '-') {
-        minus = 1;
+    while (CUR == '-') {
+        minus = 1 - minus;
 	NEXT;
 	SKIP_BLANKS;
     }