Hi

We're running into a problem with building 25.11.3 for Ubuntu Bionic.  When the cgroup/v2 plugin is building, ebpf throws an error:

```

../../../../../src/plugins/cgroup/v2/ebpf.c:38:10: fatal error: linux/mount.h: No such file or directory

 #include <linux/mount.h>

          ^~~~~~~~~~~~~~~

compilation terminated.

Makefile:638: recipe for target 'ebpf.lo' failed

make[6]: *** [ebpf.lo] Error 1

make[6]: Leaving directory '/build/slurm-25.11.3/obj-x86_64-linux-gnu/src/plugins/cgroup/v2'

```

I think this is because on Ubuntu, the `mounts.h` header is in the path `sys`- the manpage for mounts(2) describes including this file via `#include <sys/mounts.h>`.  `ebpf.c` seems to be the only place where the `linux/mounts.h` path is used, everywhere else using `sys`.

Curiously it seems to build OK on Noble (Ubuntu 24).  I have no explanation for the difference.

Has anyone run into this problem building on Ubuntu?  This include looks to have been a recent add so might be a bug, but I feel like someone else would have run into this already if it were.

Thanks

 - Michael