ARM QEMU: Unknown syscall 397

[rinigus]

QEMU is reporting

```
Unknown syscall 397
```

(statx if I read tables right) when used via flatpak for ARM images on x86_64. This has been reproduced on Fedora and Gentoo.

To reproduce:

- get flatpak KDE 5.12 for arm:

flatpak install --user org.kde.Sdk/arm/5.12 org.kde.Platform/arm/5.12

- run qmake inside Sdk:

QEMU_STRACE=1 flatpak run --filesystem=host --command=qmake org.kde.Sdk/arm/5.12 .

You will get a host of messages with unknown syscall. In practice, qmake will fail to find .pro files if you have them in that folder and libraries in the system.

As far as I understand, Flatpak images are built on AARCH64 hardware.

My config on Gentoo:

kernel: 4.19.86-gentoo x86_64
app-emulation/qemu: ~4.2.0-r1 , same with 4.0.0

[Laurent Vivier (laurent-vivier)]

New syscall definitions for ARM have been added lately by:

73209e1f15c6 ("linux-user: arm: Update syscall numbers to kernel 5.5 level")

It will available in QEMU 5.0