pread does not work right under qemu-sh4

The pread system call returns a wrong value in some case, in a program running under qemu-sh4 (version 2.9.0).

How to reproduce:
- Compile the program:
  sh4-linux-gnu-gcc-5 -O -Wall -static -o test-pread test-pread.c
- Set environment variable for using qemu-sh4 (actually not needed, since the program is statically linked here).
- ~/inst-qemu/2.9.0/bin/qemu-sh4 test-pread

Expected output:
ret=1 errno=0

Actual output:
ret=0 errno=2
test-pread.c:44: assertion 'ret == 1' failed
qemu: uncaught target signal 6 (Aborted) - core dumped





In case it matters: My host platform is Linux/x86_64.

The behaviour in qemu-2.10 is the same as in qemu-2.9.

This might be related to this fix:

> https://git.qemu.org/?p=qemu.git;a=commit;h=8bf8e9df4a7d82c7a47cc961c9cdee1615595de0

FWIW, if you're interested in sh4, please join #debian-ports on OFTC and subscribe to the debian-superh mailing list. We're doing lots of sh4 development and testing QEMU in Debian.

With qemu-2.11:
$ ~/inst-qemu/2.11.0/bin/qemu-sh4 test-pread
ret=1 errno=2

The value of errno is actually irrelevant here. So, the bug is fixed.