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