Without, the LTO compiler will complain:
[...]
LD init/built-in.o
LDFINAL vmlinux.o
arch/mips/sgi-ip27/ip27-irq.c:379:22: warning: type of ‘rt_timer_irq’ does not match original declaration [enabled by default]
extern unsigned int rt_timer_irq;
^
arch/mips/sgi-ip27/ip27-timer.c:72:5: note: previously declared here
int rt_timer_irq;
^
MODPOST vmlinux.o
[...]
And without LTO, it's still good stile to things match.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
9fcb705929