diff --git a/src/cmd/cgo/main.go b/src/cmd/cgo/main.go
index f5829123716..fb5074e8140 100644
--- a/src/cmd/cgo/main.go
+++ b/src/cmd/cgo/main.go
@@ -15,6 +15,7 @@ import (
 	"flag"
 	"fmt"
 	"go/ast"
+	"go/printer"
 	"go/token"
 	"io"
 	"os"
@@ -158,6 +159,13 @@ func main() {
 		os.Exit(2)
 	}
 
+	if *godefs || *cdefs {
+		// Generating definitions pulled from header files,
+		// to be checked into Go repositories.
+		// Line numbers are just noise.
+		conf.Mode &^= printer.SourcePos
+	}
+
 	args := flag.Args()
 	if len(args) < 1 {
 		usage()