hwdb: add Oracle Cloud OCI IMDS data - #4

sd_journal_get_data() can return a MESSAGE data object whose payload does
not start with "MESSAGE=", e.g. when the journal file is corrupted. Instead
of aborting the whole process, log and skip over such an entry like we do for
other bad/missing fields.

[   87.287390] post.sh[1619]: + journalctl -q -o short-monotonic --grep 'didn'\''t pass validation'
[   87.287844] post.sh[1620]: + grep -v test-varlink-idl
[   87.325676] post.sh[1619]: Assertion 'message = startswith(message, "MESSAGE=")' failed at src/journal/journalctl-show.c:261, function show(). Aborting.

 #0  0x00007fb47b49a29c n/a (libc.so.6 + 0x9a29c)
 #1  0x00007fb47b43e7d0 raise (libc.so.6 + 0x3e7d0)
 #2  0x00007fb47b425681 abort (libc.so.6 + 0x25681)
 #3  0x00007fb47b8a1ace log_assert_failed (libsystemd-shared-261~rc2.so + 0xa1ace)
 #4  0x000055f8e1ef9ddb show (journalctl + 0xcddb)
 systemd#5  0x000055f8e1efa6ee action_show (journalctl + 0xd6ee)
 systemd#6  0x000055f8e1ef3c20 run (journalctl + 0x6c20)
 systemd#7  0x00007fb47b427741 n/a (libc.so.6 + 0x27741)
 systemd#8  0x00007fb47b427879 __libc_start_main (libc.so.6 + 0x27879)
 systemd#9  0x000055f8e1ef4915 _start (journalctl + 0x7915)

Co-developed-by: Claude Opus 4.8 <[email protected]>

On i386 with musl and libucontext, many tests crash with SIGSEGV
when using fibers implemented on top of ucontext APIs.

For example:
```
 929/1498 libsystemd - systemd:test-event-future                                   FAIL             0.97s   killed by signal 11 SIGSEGV
/* test_sd_event_run_timer */
run-suspend-timer: Scheduling fiber
/home/pmos/build/src/systemd-261-rc3/tools/test-crash-trace.sh: line 18: 19994 Segmentation fault         (core dumped) "$@"
===== exit 139 — replaying under gdb =====
/* test_sd_event_run_timer */
run-suspend-timer: Scheduling fiber

Program received signal SIGSEGV, Segmentation fault.
0xf7d68be3 in sd_event_add_time_relative (e=0xf7ffd3f0, ret=0xf7b01fa0, clock=1, usec=10000, accuracy=0, callback=0x565564ad <inner_timer_handler>, userdata=0xf7b01fa4) at ../src/libsystemd/sd-event/sd-event.c:1455
1455	                void *userdata) {

Thread 1 (process 20485 "test-event-futu"):
 #0  0xf7d68be3 in sd_event_add_time_relative (e=0xf7ffd3f0, ret=0xf7b01fa0, clock=1, usec=10000, accuracy=0, callback=0x565564ad <inner_timer_handler>, userdata=0xf7b01fa4) at ../src/libsystemd/sd-event/sd-event.c:1455
        t = 17868423377094431728
        r = <optimized out>
 #1  0x565574c7 in sd_event_run_timer_fiber (userdata=0x0) at ../src/libsystemd/sd-event/test-event-future.c:329
        inner = 0xf7ffd3f0
        source = 0x0
        counter = 0
        r = <optimized out>
 #2  0xf7dab308 in fiber_entry_point () at ../src/libsystemd/sd-future/fiber.c:208
        _cleanup_log_unset_prefix_5 = 0x0
        __unique_prefix_c6 = 0x5655bb30
        f = 0xf7b06840
        __func__ = "fiber_entry_point"
        fake_stack_save = <optimized out>
 #3  0xf7b032ae in setcontext () from /lib/libucontext.so.1
 No symbol table info available.
 #4  0x00000000 in ?? ()
 No symbol table info available.
```

Building systemd with -mstackrealign makes all observed failures
disappear, suggesting a stack alignment issue in the interaction
between compiler-generated code and the ucontext implementation.

This resembles historical stack alignment issues in glibc's i386
makecontext() implementation, which required fixes to preserve the
expected stack alignment.

As a workaround, add -mstackrealign when building on i386 with musl
and libucontext.

Suggested-by: ChatGPT (OpenAI)