Calls to open() from within glibc cannot be intercepted
(see <http://cygwin.com/ml/libc-alpha/2006-04/msg00094.html>);
thus, include wrappers for fopen() and fclose() as well.

This should possibly be done for fdopen() and freopen(),
too, if there's need for it.

[Patch corrected and original description translated by Julius Plenz]
Signed-off-by: Julius Plenz <plenz@cis.fu-berlin.de>