Allow debugging with SOONG_DELVE=<listen addr>

Allow running Soong in a headless delve debugger by passing
SOONG_DELVE=<listen addr> in the environment.

Bug: 80165685
Test: SOONG_DELVE=:1234 m nothing
Change-Id: Icfc893c8a8354a9bbc99112d9c83259cb41906d1

ui/build/sandbox_linux.go

@@ -162,6 +162,10 @@ func (c *Cmd) wrapSandbox() {
 		c.ctx.Printf("AllowBuildBrokenUsesNetwork: %v", c.Sandbox.AllowBuildBrokenUsesNetwork)
 		c.ctx.Printf("BuildBrokenUsesNetwork: %v", c.config.BuildBrokenUsesNetwork())
 		sandboxArgs = append(sandboxArgs, "-N")
+	} else if dlv, _ := c.config.Environment().Get("SOONG_DELVE"); dlv != "" {
+		// The debugger is enabled and soong_build will pause until a remote delve process connects, allow
+		// network connections.
+		sandboxArgs = append(sandboxArgs, "-N")
 	}
 
 	// Stop nsjail from parsing arguments