[gdb/syscalls] Generate aarch64-linux.xml.in in update-linux-from-src.sh

Currently aarch64-linux.xml.in is skipped by update-linux-from-src.sh:
...
$ ./update-linux-from-src.sh ~/upstream/linux-stable.git/
Skipping aarch64-linux.xml.in, no syscall.tbl
  ...
$
...
and instead we use update-linux.sh.

This works fine, but requires an aarch64 system with recent system headers,
which makes it harder to pick up the latest changes in the linux kernel.

Fix this by updating ./update-linux-from-src.sh to:
- build the linux kernel headers for aarch64
- use update-linux.sh with those headers to generate
  aarch64-linux.xml.in.

Regenerating aarch64-linux.xml.in using current trunk of linux-stable gives me
these changes:
...
+  <syscall name="setxattrat" number="463"/>
+  <syscall name="getxattrat" number="464"/>
+  <syscall name="listxattrat" number="465"/>
+  <syscall name="removexattrat" number="466"/>
...
which are the same changes I see for the other architectures.

Note that the first step, building the linux kernel headers is a cross build
and should work on any architecture.

But the second step, update-linux.sh uses plain gcc rather than a cross-gcc,
so there is scope for problems, but we seem to get away with this on
x86_64-linux.

So, while we could constrain this to only generate aarch64-linux.xml.in on
aarch64-linux, I'm leaving this unconstrained.

For aarch64-linux.xml.in, this doesn't matter much to me because I got an
aarch64-linux system.

But I don't have a longaarch system, and the same approach seems to work
there.  I'm leaving this for follow-up patch though.

Tested on aarch64-linux and x86_64-linux.  Verified with shellcheck.

0 files changed, 0 insertions, 0 deletions