Delve is incompatible with musl system loader

[x-yuri]

I don't think it's the substitute-path issue because list main.main succeeds
and the preconditions doesn't seem to match.

1. What version of Delve are you using (dlv version)?

   Delve Debugger
   Version: 1.21.2
   Build: $Id: 98f8ab2662d926245917ade2f2bb38277315c7fc $
   

2. What version of Go are you using? (go version)?

   go version go1.21.5 linux/amd64
   

3. What operating system and processor architecture are you using?

   Arch Linux + Alpine Linux, x86_64

4. What did you do?

   a.sh:

   set -eu
   docker run --rm -itv "$PWD:/app" -w /app alpine:3.19 sh -euc '
       apk add go delve
       exec sh
   '

   a/a.go:

   package main
   import "fmt"
   func main() {
       fmt.Println("hello world")
   }

   $ sh a.sh
   ...
   /app # dlv debug ./cmd/dlv -- debug ./a
   Type 'help' for list of commands.
   (dlv) b cmds.execute
   Breakpoint 1 set at 0xdc4dd6 for github.com/go-delve/delve/cmd/dlv/cmds.execute() ./cmd/dlv/cmds/commands.go:943
   (dlv) c main.main
   Breakpoint 2 set at 0xe0d916 for main.main() ./cmd/dlv/main.go:14
   > main.main() ./cmd/dlv/main.go:14 (hits goroutine(1):1 total:1) (PC: 0xe0d916)
        9: )
       10:
       11: // Build is the git sha of this binaries build.
       12: var Build string
       13:
   =>  14: func main() {
       15:         if Build != "" {
       16:                 version.DelveVersion.Build = Build
       17:         }
       18:
       19:         const cgoCflagsEnv = "CGO_CFLAGS"
   (dlv) b debugCmd
   Command failed: Breakpoint exists at /app/cmd/dlv/cmds/commands.go:578 at dbf8ca
   (dlv) c
   WARN[0018] CGO_CFLAGS already set, Cgo code could be optimized.  layer=dlv
   > github.com/go-delve/delve/cmd/dlv/cmds.debugCmd() ./cmd/dlv/cmds/commands.go:578 (hits goroutine(1):1 total:1) (PC: 0xdbf8ca)
      573:                 return "", false
      574:         }
      575:         return debugname, true
      576: }
      577:
   => 578: func debugCmd(cmd *cobra.Command, args []string) {
      579:         status := func() int {
      580:                 dlvArgs, targetArgs := splitArgs(cmd, args)
      581:                 debugname, ok := buildBinary(cmd, dlvArgs, false)
      582:                 if !ok {
      583:                         return 1
   (dlv) exit
   

   So maybe I don't need to set the breakpoint?

   /app # dlv debug ./cmd/dlv -- debug ./a
   Type 'help' for list of commands.
   (dlv) b cmds.execute
   Breakpoint 1 set at 0xdc4dd6 for github.com/go-delve/delve/cmd/dlv/cmds.execute() ./cmd/dlv/cmds/commands.go:943
   (dlv) c main.main
   Breakpoint 2 set at 0xe0d916 for main.main() ./cmd/dlv/main.go:14
   > main.main() ./cmd/dlv/main.go:14 (hits goroutine(1):1 total:1) (PC: 0xe0d916)
        9: )
       10:
       11: // Build is the git sha of this binaries build.
       12: var Build string
       13:
   =>  14: func main() {
       15:         if Build != "" {
       16:                 version.DelveVersion.Build = Build
       17:         }
       18:
       19:         const cgoCflagsEnv = "CGO_CFLAGS"
   (dlv) c
   WARN[0001] CGO_CFLAGS already set, Cgo code could be optimized.  layer=dlv
   > github.com/go-delve/delve/cmd/dlv/cmds.execute() ./cmd/dlv/cmds/commands.go:943 (hits goroutine(1):1 total:1) (PC: 0xdc4dd6)
      938:                 fmt.Println(err)
      939:         }
      940:         return status
      941: }
      942:
   => 943: func execute(attachPid int, processArgs []string, conf *config.Config, coreFile string, kind debugger.ExecuteKind, dlvArgs []string, buildFlags string) int {
      944:         if err := logflags.Setup(log, logOutput, logDest); err != nil {
      945:                 fmt.Fprintf(os.Stderr, "%v\n", err)
      946:                 return 1
      947:         }
      948:         defer logflags.Close()
   (dlv) exit
   

   I need. And if I set the breakpoint before c main.main?

   /app # dlv debug ./cmd/dlv -- debug ./a
   Type 'help' for list of commands.
   (dlv) b debugCmd
   Breakpoint 1 set at 0xdbf8ca for github.com/go-delve/delve/cmd/dlv/cmds.debugCmd() ./cmd/dlv/cmds/commands.go:578
   (dlv) c main.main
   Breakpoint 2 set at 0xe0d916 for main.main() ./cmd/dlv/main.go:14
   > main.main() ./cmd/dlv/main.go:14 (hits goroutine(1):1 total:1) (PC: 0xe0d916)
        9: )
       10:
       11: // Build is the git sha of this binaries build.
       12: var Build string
       13:
   =>  14: func main() {
       15:         if Build != "" {
       16:                 version.DelveVersion.Build = Build
       17:         }
       18:
       19:         const cgoCflagsEnv = "CGO_CFLAGS"
   (dlv) c
   WARN[0001] CGO_CFLAGS already set, Cgo code could be optimized.  layer=dlv
   > github.com/go-delve/delve/cmd/dlv/cmds.debugCmd() ./cmd/dlv/cmds/commands.go:578 (hits goroutine(1):1 total:1) (PC: 0xdbf8ca)
      573:                 return "", false
      574:         }
      575:         return debugname, true
      576: }
      577:
   => 578: func debugCmd(cmd *cobra.Command, args []string) {
      579:         status := func() int {
      580:                 dlvArgs, targetArgs := splitArgs(cmd, args)
      581:                 debugname, ok := buildBinary(cmd, dlvArgs, false)
      582:                 if !ok {
      583:                         return 1
   (dlv) exit
   

5. What did you expect to see?

   I expected it to not produce errors when it succeeded.

6. What did you see instead?

   I saw the "Breakpoint exists" error.

logs with --log --log-output=rpc,dap