merged changes from branches/iostreams_dev revisions 42595-42599; applied Dinkumware implementation of positioning functions to IBM Visual Age; simplified and corrected implementation

[SVN r42600]

libs/iostreams

@@ -1 +1 @@
-Subproject commit bc7dcedcbdba18f4a9c9646f0fa246b561282eec
+Subproject commit 2d11830721a190083aeec1b937608738276492ee