libsel4bench: include autoconf.h

[axel-h]

I'm getting this error

In file included from libsel4/autoconf/autoconf.h:4,
                 from .../kernel/libsel4/include/sel4/macros.h:9,
                 from .../kernel/libsel4/include/sel4/types.h:13,
                 from .../sel4_libs/libsel4bench/include/sel4bench/kernel_logging.h:16,
                 from .../sel4_libs/libsel4bench/src/kernel_logging.c:13:
kernel/gen_config/kernel/gen_config.h:24: warning: "CONFIG_ROOT_CNODE_SIZE_BITS" redefined
 #define CONFIG_ROOT_CNODE_SIZE_BITS 15

In file included from .../sel4_libs/libsel4bench/include/sel4bench/kernel_logging.h:15,
                 from .../sel4_libs/libsel4bench/src/kernel_logging.c:13:
.../kernel/libsel4/include/sel4/config.h:17: note: this is the location of the previous definition
 #define CONFIG_ROOT_CNODE_SIZE_BITS 12

and a similar one for CONFIG_MAX_NUM_BOOTINFO_UNTYPED_CAPS and CONFIG_NUM_DOMAINS. The explanation is, that in kernel commit https://github.com/seL4/seL4/commit/1ce721b418f13e7430d379461c59b80322fc6daf the file sel4/config.h was extended to make the kernel configuration available to user space. However, it will include autoconf.h only if HAVE_AUTOCONF is defined and provide a fixed default configuration otherwise. We don't define HAVE_AUTOCONF anywhere, but include autoconf.h unconditionally instead everywhere, which leads to conflicting defines if this include is forgotten. Thus we add the missing include autoconf.h here before including sel4/config.h then.

We could also define HAVE_AUTOCONF, but I wonder if this should be considered deprecated and get removed everywhere eventually. We no longer use autoconf and CMake just mimics it keep compatibility. I wonder if there is any need for all the compatibility layers left nowaday and the change in sel4/config.h are another step away form this actually. If HAVE_AUTOCONF gets fully removed, all project could just include sel4/config.h instead of the attic autoconf.h.

Note that we could also avoid this PR if we change sel4/config.h and replace

#ifdef HAVE_AUTOCONF
#include <autoconf.h>
#endif

with simply

#include <autoconf.h>

but I wonder which additional side effects this has in other modules. So merging this PR here might be the quicker way to avoid the current problem before trying to solve this in a more general way.

[kent-mcleod]

Yea, I agree that the real bug is in seL4/seL4

[axel-h]

So let's include autoconf.h in sel4/config.h unconditionally then?

[axel-h]

OK, so once https://github.com/seL4/seL4/pull/300 is merged, we can drop this PR

[axel-h]

dropping this PR , as the too cause is fixed now.