cant find /proc/last_kemg topic

hello
i cant find /proc/last_kmsg either in kernel crash after booting or in booting
tried to add
CONFIG_APANIC=y
CONFIG_APANIC_PLABEL="android_panic123"
also nothing can found
this could be interisting
kernel/panic.c:77:1: warning: function declaration isn't a prototype [-Wstrict-prototypes]
kernel/panic.c:78:1: warning: function declaration isn't a prototype [-Wstrict-prototypes]
kernel/panic.c: In function 'panic':
kernel/panic.c:117:2: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]