single argument panic

note that sortmain.go has been run through hg gofmt;
only the formatting of the day initializers changed.
i'm happy to revert that formatting if you'd prefer.

stop on error in doc/progs/run

R=r
CC=golang-dev
https://golang.org/cl/850041
diff --git a/src/pkg/net/fd.go b/src/pkg/net/fd.go
index 5619b9e..28e85be 100644
--- a/src/pkg/net/fd.go
+++ b/src/pkg/net/fd.go
@@ -11,6 +11,7 @@
 	"os"
 	"sync"
 	"syscall"
+	"time"
 )
 
 // Network file descriptor.
@@ -176,12 +177,7 @@
 }
 
 func (s *pollServer) Now() int64 {
-	sec, nsec, err := os.Time()
-	if err != nil {
-		panic("net: os.Time: ", err.String())
-	}
-	nsec += sec * 1e9
-	return nsec
+	return time.Nanoseconds()
 }
 
 func (s *pollServer) CheckDeadlines() {