[PATCH] init.c: Expose f_out and f_err to loaded libraries via dlsym()

[PATCH] init.c: Expose f_out and f_err to loaded libraries via dlsym()

Loaded ioengines would like to use the logging functions but can't, as
they can't see f_out and f_err.  Create get_f_{out,err}() so that
the libraries can dlsym() them.  Compile fio with -rdynamic so dlopen()
works.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>