Fix for bug 15633. Fixing build warning with the patch submitted by James Clark (jjc@jclark.com). r=nisheeth

expat/xmlparse/xmlparse.c

@@ -2009,8 +2009,7 @@ initializeEncoding(XML_Parser parser)
     int i;
     for (i = 0; protocolEncodingName[i]; i++) {
       if (i == sizeof(encodingBuf) - 1
-	  || protocolEncodingName[i] >= 0x80
-	  || protocolEncodingName[i] < 0) {
+	  || (protocolEncodingName[i] & ~0x7f) != 0) {
 	encodingBuf[0] = '\0';
 	break;
       }

parser/expat/lib/xmlparse.c

@@ -2009,8 +2009,7 @@ initializeEncoding(XML_Parser parser)
     int i;
     for (i = 0; protocolEncodingName[i]; i++) {
       if (i == sizeof(encodingBuf) - 1
-	  || protocolEncodingName[i] >= 0x80
-	  || protocolEncodingName[i] < 0) {
+	  || (protocolEncodingName[i] & ~0x7f) != 0) {
 	encodingBuf[0] = '\0';
 	break;
       }