[PATCH] ARM: dyndbg: allow including dyndbg.h in decompressor

[Vincenzo Palazzo]

> From: Arnd Bergmann <arnd at arndb.de>
>
> After a change to linux/module.h, dyndbg.h is now included
> indirectly from the decompressor for lz4 support, which in turn
> causes a build failure on 32-bit Arm:
>
> In file included from include/linux/module.h:30,
>                  from arch/arm/boot/compressed/../../../../lib/lz4/lz4_decompress.c:39,
>                  from arch/arm/boot/compressed/../../../../lib/decompress_unlz4.c:10,
>                  from arch/arm/boot/compressed/decompress.c:59:
> include/linux/dynamic_debug.h: In function 'ddebug_dyndbg_module_param_cb':
> include/linux/dynamic_debug.h:307:14: error: implicit declaration of function 'strcmp' [-Werror=implicit-function-declaration]
>   307 |         if (!strcmp(param, "dyndbg")) {
>       |              ^~~~~~
> include/linux/dynamic_debug.h:1:1: note: 'strcmp' is defined in header '<string.h>'; did you forget to '#include <string.h>'?
>   +++ |+#include <string.h>
>
> The decompressor has its own replacement for the linux/string.h contents,
> so the normal declaration is not visible here. Since the function is
> not actually called, it is sufficient to add a declaration, and this
> is in fact the correct one as it matches the definition in
> arch/arm/boot/compressed/string.c.
>
> Fixes: 7deabd674988 ("dyndbg: use the module notifier callbacks")
> Signed-off-by: Arnd Bergmann <arnd at arndb.de>
> ---

Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev at gmail.com>