Linux 6.8 compat: implement strlcpy fallback

Linux has removed strlcpy in favour of strscpy. This implements a
fallback implementation of strlcpy for this case.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Sponsored-by: https://despairlabs.com/sponsor/
Closes #15805

module/os/linux/spl/spl-kstat.c

@@ -32,6 +32,7 @@
 #include <sys/vmem.h>
 #include <sys/cmn_err.h>
 #include <sys/sysmacros.h>
+#include <sys/string.h>
 
 static kmutex_t kstat_module_lock;
 static struct list_head kstat_module_list;