fixing compilations when disabling parts of the library at configure time.

* runsuite.c runtest.c tree.c: fixing compilations when
  disabling parts of the library at configure time.
Daniel
diff --git a/runsuite.c b/runsuite.c
index 23e98a5..e9fcc0c 100644
--- a/runsuite.c
+++ b/runsuite.c
@@ -743,7 +743,7 @@
 
 static int
 xstcTestInstance(int verbose, xmlNodePtr cur, xmlSchemaPtr schemas,
-                 const xmlChar *spath, const xmlChar *base) {
+                 const xmlChar *spath, const char *base) {
     xmlChar *href = NULL;
     xmlChar *path = NULL;
     xmlChar *validity = NULL;
@@ -952,7 +952,7 @@
     xmlNodePtr cur;
     xmlChar *contributor;
     xmlChar *name;
-    int ret;
+    int ret = 0;
 
     doc = xmlReadFile(metadata, NULL, XML_PARSE_NOENT);
     if (doc == NULL) {