Changeset 2d733c42 in rtems for c/src/exec/libcsupport/src/ftruncate.c

More general fix based on bug report and patch from Ian Lance Taylor
<ian@…> to fix this problem:

There is a small bug in rtems_close in c/src/lib/libc/libio.c. It
does not check whether the file descriptor it is passed is open. This
can cause it to make a null dereference if it is passed a file
descriptor which is in the valid range but which was not opened, or
which was already closed.