libgo: restore building on Solaris

Add build tags and a few other changes so that libgo builds on Solaris.

Patch partially from Rainer Orth.

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/386215

gcc/go/gofrontend/MERGE

-0af68c0552341a44f1fb12301f9eff954b9dde88
+3742e8a154bfec805054b4ebf0809f12dc7694da
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/net/fcntl_libc_test.go

@@ -6,7 +6,10 @@
 
 package net
 
-import "syscall"
+import (
+	"syscall"
+	_ "unsafe"
+)
 
 // Use a helper function to call fcntl.  This is defined in C in
 // libgo/runtime.

libgo/go/os/signal/internal/pty/pty.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build (aix || darwin || dragonfly || freebsd || hurd || (linux && !android) || netbsd || openbsd) && cgo
+//go:build (aix || darwin || dragonfly || freebsd || hurd || (linux && !android) || netbsd || openbsd || solaris) && cgo
 
 // Package pty is a simple pseudo-terminal package for Unix systems,
 // implemented by calling C functions via cgo.

libgo/go/runtime/os3_solaris.go

@@ -36,6 +36,14 @@ func solarisExecutablePath() string {
 	return executablePath
 }
 
+func setProcessCPUProfiler(hz int32) {
+	setProcessCPUProfilerTimer(hz)
+}
+
+func setThreadCPUProfiler(hz int32) {
+	setThreadCPUProfilerHz(hz)
+}
+
 //go:nosplit
 func validSIGPROF(mp *m, c *sigctxt) bool {
 	return true

libgo/go/runtime/stubs2.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !aix && !darwin && !js && !openbsd && !plan9 && !solaris && !windows
+//go:build !js && !plan9 && !windows
 
 package runtime
 

libgo/go/syscall/exec_bsd.go

@@ -143,13 +143,13 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 	// User and groups
 	if cred := sys.Credential; cred != nil {
 		ngroups := len(cred.Groups)
-		var groups *Gid_t
+		var groups unsafe.Pointer
 		if ngroups > 0 {
 			gids := make([]Gid_t, ngroups)
 			for i, v := range cred.Groups {
 				gids[i] = Gid_t(v)
 			}
-			groups = &gids[0]
+			groups = unsafe.Pointer(&gids[0])
 		}
 		if !cred.NoSetGroups {
 			err1 = raw_setgroups(ngroups, groups)

libgo/go/syscall/export_unix_test.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build dragonfly || freebsd || hurd || linux || netbsd || openbsd
+//go:build dragonfly || freebsd || hurd || linux || netbsd || openbsd || solaris
 
 package syscall
 

libgo/go/syscall/syscall_solaris.go

@@ -6,8 +6,6 @@ package syscall
 
 import "unsafe"
 
-const _F_DUP2FD_CLOEXEC = F_DUP2FD_CLOEXEC
-
 func (ts *Timestruc) Unix() (sec int64, nsec int64) {
 	return int64(ts.Sec), int64(ts.Nsec)
 }