syscall: Change raw_ioctl cmd type to uintptr.

    
    Attempt to fix a build bug report:
    
    ../../../../libgo/go/syscall/exec_linux.go:185:37: error: integer constant overflow
       _, err1 = raw_ioctl_ptr(sys.Ctty, TIOCSPGRP, unsafe.Pointer(&pgrp))
    
    Reviewed-on: https://go-review.googlesource.com/16539

From-SVN: r229674

gcc/go/gofrontend/MERGE

-6b4b969f552b8f9ac87a715d5ad06e52bd031b60
+e9550aa81d38ada037f675f50cbc09e6f1c35c12
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

libgo/go/syscall/exec_unix.go

@@ -41,10 +41,10 @@ import (
 //sysnb	raw_close(fd int) (err Errno)
 //close(fd _C_int) _C_int
 
-//sysnb	raw_ioctl(fd int, cmd int, val int) (rval int, err Errno)
+//sysnb	raw_ioctl(fd int, cmd uintptr, val int) (rval int, err Errno)
 //__go_ioctl(fd _C_int, cmd _C_int, val _C_int) _C_int
 
-//sysnb raw_ioctl_ptr(fd int, cmd int, val unsafe.Pointer) (rval int, err Errno)
+//sysnb raw_ioctl_ptr(fd int, cmd uintptr, val unsafe.Pointer) (rval int, err Errno)
 //__go_ioctl_ptr(fd _C_int, cmd _C_int, val unsafe.Pointer) _C_int
 
 //sysnb	raw_execve(argv0 *byte, argv **byte, envv **byte) (err Errno)