Eliminate a couple of evil common declarations.

sys/alpha/alpha/interrupt.c

@@ -57,6 +57,7 @@ struct evcnt clock_intr_evcnt;	/* event counter for clock intrs. */
 #endif
 
 volatile int mc_expected, mc_received;
+u_int32_t intr_nesting_level;
 
 static void 
 dummy_perf(unsigned long vector, struct trapframe *framep)  

sys/alpha/alpha/trap.c

@@ -68,6 +68,7 @@
 #include <ddb/ddb.h>
 #endif
 
+u_int32_t want_resched;
 u_int32_t astpending;
 struct proc *fpcurproc;		/* current user of the FPU */
 

sys/alpha/include/cpu.h

@@ -92,8 +92,8 @@ struct clockframe {
 #define	aston()		(astpending = 1)
 
 #ifdef _KERNEL
-u_int32_t intr_nesting_level;	/* bookeeping only; counts software intr */
-u_int32_t want_resched;		/* resched() was called */
+extern u_int32_t intr_nesting_level;	/* bookeeping only; counts sw intrs */
+extern u_int32_t want_resched;		/* resched() was called */
 #endif