Fail to compile for termux

[chfanghr]

Please answer the following before submitting your issue:

Note: Please include any substantial examples (debug session output,
stacktraces, etc) as linked gists.

1. What version of Delve are you using (dlv version)?
   Master branch
2. What version of Go are you using? (go version)?
   1.11.4
3. What operating system and processor architecture are you using?
   Linux localhost 3.10.104 add exit command to docs and help #4 SMP PREEMPT Fri Dec 14 15:02:40 CST 2018 aarch64 Android
4. What did you do?

u0_a34@localhost ~> go get -u -v github.com/derekparker/delve/cmd/dlv    
github.com/derekparker/delve (download)                                               
github.com/derekparker/delve/pkg/proc                                                
# github.com/derekparker/delve/pkg/proc                                               
go/src/github.com/derekparker/delve/pkg/proc/disasm.go:12:14: undefined: archInst

5. What did you expect to see?
6. What did you see instead?

[aarzilli]

Duplicate of #118