Fixed typo in xmlCharEncFirstLine pointed out by Mark Rowe (bug #440159)

* encoding.c: Fixed typo in xmlCharEncFirstLine pointed out
  by Mark Rowe (bug #440159)
* include/libxml/xmlversion.h.in: Added check for definition of
  _POSIX_C_SOURCE to avoid warnings on Apple OS/X (patch from
  Wendy Doyle and Mark Rowe, bug #346675)
* schematron.c, testapi.c, tree.c, xmlIO.c, xmlsave.c: minor
  changes to fix compilation warnings - no change to logic.

svn path=/trunk/; revision=3618
diff --git a/xmlIO.c b/xmlIO.c
index f576d76..154fcf8 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -3638,7 +3638,7 @@
  *
  * Returns a new allocated URL, or NULL.
  */
-xmlChar *
+static xmlChar *
 xmlResolveResourceFromCatalog(const char *URL, const char *ID,
                               xmlParserCtxtPtr ctxt) {
     xmlChar *resource = NULL;