syscall: fix TestForeground for AIX

On AIX, sys.Pgid must be a int32 and not a int64 as on Solaris for ioctl
syscall.
Pid_t type can be used to provide the same code in both OS. But pid_t
must be added to ztypes_solaris_amd64.go.

Change-Id: I1dbe57f099f9e5ac9491aaf246a521137eea5014
Reviewed-on: https://go-review.googlesource.com/c/144539
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/syscall/exec_libc.go

@@ -124,14 +124,14 @@ func forkAndExecInChild(argv0 *byte, argv, envv []*byte, chroot, dir *byte, attr
 	}
 
 	if sys.Foreground {
-		pgrp := sys.Pgid
+		pgrp := _Pid_t(sys.Pgid)
 		if pgrp == 0 {
 			r1, err1 = getpid()
 			if err1 != 0 {
 				goto childerror
 			}
 
-			pgrp = int(r1)
+			pgrp = _Pid_t(r1)
 		}
 
 		// Place process group in foreground.

src/syscall/syscall_aix.go

@@ -184,15 +184,15 @@ func ReadDirent(fd int, buf []byte) (n int, err error) {
 	return getdirent(fd, buf)
 }
 
-//sys  wait4(pid Pid_t, status *_C_int, options int, rusage *Rusage) (wpid Pid_t, err error)
+//sys  wait4(pid _Pid_t, status *_C_int, options int, rusage *Rusage) (wpid _Pid_t, err error)
 func Wait4(pid int, wstatus *WaitStatus, options int, rusage *Rusage) (wpid int, err error) {
 	var status _C_int
-	var r Pid_t
+	var r _Pid_t
 	err = ERESTART
 	// AIX wait4 may return with ERESTART errno, while the processus is still
 	// active.
 	for err == ERESTART {
-		r, err = wait4(Pid_t(pid), &status, options, rusage)
+		r, err = wait4(_Pid_t(pid), &status, options, rusage)
 	}
 	wpid = int(r)
 	if wstatus != nil {

src/syscall/types_aix.go

@@ -86,7 +86,7 @@ type Rusage C.struct_rusage
 
 type Rlimit C.struct_rlimit
 
-type Pid_t C.pid_t
+type _Pid_t C.pid_t
 
 type _Gid_t C.gid_t
 

src/syscall/types_solaris.go

@@ -101,6 +101,8 @@ type Rusage C.struct_rusage
 
 type Rlimit C.struct_rlimit
 
+type _Pid_t C.pid_t
+
 type _Gid_t C.gid_t
 
 // Files

src/syscall/zsyscall_aix_ppc64.go

@@ -420,9 +420,9 @@ func getdirent(fd int, buf []byte) (n int, err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
-func wait4(pid Pid_t, status *_C_int, options int, rusage *Rusage) (wpid Pid_t, err error) {
+func wait4(pid _Pid_t, status *_C_int, options int, rusage *Rusage) (wpid _Pid_t, err error) {
 	r0, _, e1 := syscall6(uintptr(unsafe.Pointer(&libc_wait4)), 4, uintptr(pid), uintptr(unsafe.Pointer(status)), uintptr(options), uintptr(unsafe.Pointer(rusage)), 0, 0)
-	wpid = Pid_t(r0)
+	wpid = _Pid_t(r0)
 	if e1 != 0 {
 		err = errnoErr(e1)
 	}

src/syscall/ztypes_aix_ppc64.go

@@ -64,7 +64,7 @@ type Rlimit struct {
 	Max uint64
 }
 
-type Pid_t int32
+type _Pid_t int32
 
 type _Gid_t uint32
 

src/syscall/ztypes_solaris_amd64.go

@@ -60,6 +60,8 @@ type Rlimit struct {
 	Max uint64
 }
 
+type _Pid_t int32
+
 type _Gid_t uint32
 
 const (