runtime: move NumCPU declaration into debug.go.

R=rsc
CC=golang-dev
https://golang.org/cl/5574060

src/pkg/runtime/debug.go

@@ -23,6 +23,9 @@ func UnlockOSThread()
 // This call will go away when the scheduler improves.
 func GOMAXPROCS(n int) int
 
+// NumCPU returns the number of logical CPUs on the local machine.
+func NumCPU() int
+
 // Cgocalls returns the number of cgo calls made by the current process.
 func Cgocalls() int64
 

src/pkg/runtime/extern.go

@@ -68,9 +68,6 @@ func funcline_go(*Func, uintptr) (string, int)
 // mid returns the current os thread (m) id.
 func mid() uint32
 
-// NumCPU returns the number of logical CPUs on the local machine.
-func NumCPU() int
-
 // Semacquire waits until *s > 0 and then atomically decrements it.
 // It is intended as a simple sleep primitive for use by the synchronization
 // library and should not be used directly.