[PATCH] io.c (do_io_advise): raise exception without segfaulting
ruby 2.0.0dev (2012-02-25 trunk 34796) [x86_64-linux]
IO objects (e.g. pipes) may have Qnil for fptr->pathv. Calling
RSTRING_PTR on Qnil is unsafe and causes a segmentation fault.
This issue also affects 1.9.3 and will need to be backported.