Generate g for ~ Go 1.16beta1 (go1.16beta1-34-g4fd9455882)
Compared to Go1.15 there are only cosmetic changes:

    --- a/zruntime_g_go1.15.go
    +++ b/zruntime_g_go1.16.go
    @@ -1,6 +1,6 @@
     // Code generated by g_typedef; DO NOT EDIT.

    -// +build go1.15,!go1.16
    +// +build go1.16,!go1.17

     package xruntime

    @@ -144,7 +144,7 @@ type gobuf struct {
     	ctxt unsafe.Pointer
     	ret  uintreg
     	lr   uintptr
    -	bp   uintptr // for GOEXPERIMENT=framepointer
    +	bp   uintptr // for framepointer-enabled architectures
     }
     type funcval struct {
     	fn uintptr
    @@ -158,6 +158,8 @@ type timer struct {
     	// Timer wakes up at when, and then at when+period, ... (period > 0 only)
     	// each time calling f(arg, now) in the timer goroutine, so f must be
     	// a well-behaved function and not block.
    +	//
    +	// when must be positive on an active timer.
     	when   int64
     	period int64
     	f      func(interface{}, uintptr)

Regenerated files stay without changes for Go1.15 and previous releases.