final batch for "declared and not used"

 * update mksyscall.sh and rebuild syscall/z*.go
 * fix a few linux-only files

R=r
DELTA=455  (12 added, 1 deleted, 442 changed)
OCL=34637
CL=34655

src/pkg/debug/proc/proc_linux.go

@@ -421,7 +421,6 @@ func (p *process) uninstallBreakpoints() os.Error {
 // event.
 func (t *thread) wait() {
 	for {
-		var err os.Error;
 		var ev debugEvent;
 		ev.t = t;
 		t.logTrace("beginning wait");
@@ -764,7 +763,7 @@ func (p *process) do(f func () os.Error) os.Error {
 // stopMonitor stops the monitor with the given error.  If the monitor
 // is already stopped, does nothing.
 func (p *process) stopMonitor(err os.Error) {
-	doNotBlock := p.stopReq <- err;
+	_ = p.stopReq <- err;	// do not block
 	// TODO(austin) Wait until monitor has exited?
 }
 
@@ -1215,7 +1214,7 @@ func (p *process) attachAllThreads() os.Error {
 				continue;
 			}
 
-			t, err := p.attachThread(tid);
+			_, err = p.attachThread(tid);
 			if err != nil {
 				// There could have been a race, or
 				// this process could be a zobmie.
@@ -1309,7 +1308,7 @@ func ForkExec(argv0 string, argv []string, envv []string, dir string, fd []*os.F
 		p.pid = pid;
 
 		// The process will raise SIGTRAP when it reaches execve.
-		t, err := p.newThread(pid, syscall.SIGTRAP, false);
+		_, err := p.newThread(pid, syscall.SIGTRAP, false);
 		return err;
 	});
 	if err != nil {

src/pkg/net/fd_linux.go

@@ -135,7 +135,7 @@ func (p *pollster) WaitFD(nsec int64) (fd int, mode int, err os.Error) {
 	}
 
 	// Other events are error conditions - wake whoever is waiting.
-	events, already := p.events[fd];
+	events, _ := p.events[fd];
 	if events & writeFlags != 0 {
 		p.StopWaiting(fd, writeFlags);
 		return fd, 'w', nil;

src/pkg/syscall/mksyscall.sh

@@ -127,17 +127,21 @@ while(<>) {
 
 	# Actual call.
 	my $args = join(', ', @args);
-	$text .= "\tr0, r1, e1 := $asm($sysname, $args);\n";
+	my $call = "$asm($sysname, $args)";
 
 	# Assign return values.
+	my $body = "";
+	my @ret = ("_", "_", "_");
 	for(my $i=0; $i<@out; $i++) {
 		my $p = $out[$i];
 		my ($name, $type) = parseparam($p);
 		my $reg = "";
 		if($name eq "errno") {
 			$reg = "e1";
+			$ret[2] = $reg;
 		} else {
 			$reg = sprintf("r%d", $i);
+			$ret[$i] = $reg;
 		}
 		if($type eq "bool") {
 			$reg = "$reg != 0";
@@ -152,10 +156,18 @@ while(<>) {
 			} else {
 				$reg = sprintf("int64(r%d)<<32 | int64(r%d)", $i+1, $i);
 			}
+			$ret[$i] = sprintf("r%d", $i);
+			$ret[$i+1] = sprintf("r%d", $i+1);
 			$i++;		# loop will do another $i++
 		}
-		$text .= "\t$name = $type($reg);\n";
+		$body .= "\t$name = $type($reg);\n";
 	}
+	if ($ret[0] eq "_" && $ret[1] eq "_" && $ret[2] eq "_") {
+		$text .= "\t$call;\n";
+	} else {
+		$text .= "\t$ret[0], $ret[1], $ret[2] := $call;\n";
+	}
+	$text .= $body;
 
 	$text .= "\treturn;\n";
 	$text .= "}\n\n";

src/pkg/syscall/syscall_linux.go

@@ -180,7 +180,7 @@ func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int,
 
 func Sleep(nsec int64) (errno int) {
 	tv := NsecToTimeval(nsec);
-	n, err := Select(0, nil, nil, nil, &tv);
+	_, err := Select(0, nil, nil, nil, &tv);
 	return err;
 }