This fixes the following error with musl libc:
In file included from start.c:59:0:
log.h: In function 'lxc_log_priority_to_int':
log.h:136:2: error: implicit declaration of function 'strcasecmp' [-Werror=implicit-function-declaration]
Signed-off-by: Natanael Copa <ncopa@alpinelinux.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>