[dev.cc] all: merge dev.power64 (7667e41f3ced) into dev.cc

This is to reduce the delta between dev.cc and dev.garbage to just garbage collector changes.

These are the files that had merge conflicts and have been edited by hand:
        malloc.go
        mem_linux.go
        mgc.go
        os1_linux.go
        proc1.go
        panic1.go
        runtime1.go

LGTM=austin
R=austin
CC=golang-codereviews
https://codereview.appspot.com/174180043

4 files changed, 5 insertions, 2 deletions

diff --git a/src/os/exec/exec_test.go b/src/os/exec/exec_test.go
index bc9c00eff..197d3e8b4 100644
--- a/src/os/exec/exec_test.go
+++ b/src/os/exec/exec_test.go
@@ -246,7 +246,7 @@ func TestPipeLookPathLeak(t *testing.T) {
 }
 
 func numOpenFDS(t *testing.T) (n int, lsof []byte) {
-	lsof, err := exec.Command("lsof", "-n", "-p", strconv.Itoa(os.Getpid())).Output()
+	lsof, err := exec.Command("lsof", "-b", "-n", "-p", strconv.Itoa(os.Getpid())).Output()
 	if err != nil {
 		t.Skip("skipping test; error finding or running lsof")
 	}
diff --git a/src/os/file_plan9.go b/src/os/file_plan9.go
index 5efc2a4f1..132594eed 100644
--- a/src/os/file_plan9.go
+++ b/src/os/file_plan9.go
@@ -25,7 +25,8 @@ type file struct {
 	dirinfo *dirInfo // nil unless directory being read
 }
 
-// Fd returns the integer Unix file descriptor referencing the open file.
+// Fd returns the integer Plan 9 file descriptor referencing the open file.
+// The file descriptor is valid only until f.Close is called or f is garbage collected.
 func (f *File) Fd() uintptr {
 	if f == nil {
 		return ^(uintptr(0))
diff --git a/src/os/file_unix.go b/src/os/file_unix.go
index f59d563e6..ff4fc7d12 100644
--- a/src/os/file_unix.go
+++ b/src/os/file_unix.go
@@ -29,6 +29,7 @@ type file struct {
 }
 
 // Fd returns the integer Unix file descriptor referencing the open file.
+// The file descriptor is valid only until f.Close is called or f is garbage collected.
 func (f *File) Fd() uintptr {
 	if f == nil {
 		return ^(uintptr(0))
diff --git a/src/os/file_windows.go b/src/os/file_windows.go
index 3b5519390..2a90a5055 100644
--- a/src/os/file_windows.go
+++ b/src/os/file_windows.go
@@ -36,6 +36,7 @@ type file struct {
 }
 
 // Fd returns the Windows handle referencing the open file.
+// The handle is valid only until f.Close is called or f is garbage collected.
 func (file *File) Fd() uintptr {
 	if file == nil {
 		return uintptr(syscall.InvalidHandle)