From: Carlos R. Mafra <crmafra@ift.unesp.br>

When CONFIG_HPET_EMULATE_RTC is defined the external declaration of
hpet_rtc_interrupt is redundant due to the inclusion of hpet.h.

When !CONFIG_HPET_EMULATE_RTC we make it clear that hpet_rtc_interrupt is
not used by defining it to return zero.

Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/char/rtc.c     |    2 --
 drivers/rtc/rtc-cmos.c |    5 ++++-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff -puN drivers/char/rtc.c~rtc-remove-and-clarify-unneeded-externs drivers/char/rtc.c
--- a/drivers/char/rtc.c~rtc-remove-and-clarify-unneeded-externs
+++ a/drivers/char/rtc.c
@@ -120,8 +120,6 @@ static irqreturn_t hpet_rtc_interrupt(in
 	return 0;
 }
 #endif
-#else
-extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
 #endif
 
 /*
diff -puN drivers/rtc/rtc-cmos.c~rtc-remove-and-clarify-unneeded-externs drivers/rtc/rtc-cmos.c
--- a/drivers/rtc/rtc-cmos.c~rtc-remove-and-clarify-unneeded-externs
+++ a/drivers/rtc/rtc-cmos.c
@@ -52,7 +52,10 @@
 #define hpet_rtc_timer_init() 			do { } while (0)
 #define hpet_register_irq_handler(h) 		0
 #define hpet_unregister_irq_handler(h)		do { } while (0)
-extern irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id);
+static irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id)
+{
+	return 0;
+}
 #endif
 
 struct cmos_rtc {
_