macOS: development troubleshooting

Problem: developer mode is not enabled

lldb debugger refuses to run with message:

developer mode is not enabled on this machine and this is a non-interactive debug session

Possible solution:

Enable developer mode with
```
sudo DevToolsSecurity -enable
```
Problem: lldb or gdb is not codesigned

When trying to debug with lldb and gdb they stop with a message

Unable to find Mach task port for process-id

Possible solution:

The lldb or gdb executable must be codesigned. The procedure is explained in lldb docs: code-signing.txt

Additionally, when installing gdb using Homebrew (brew install gdb), it recommends the following:

gdb requires special privileges to access Mach ports. You will need to codesign the binary. For instructions, see:

https://sourceware.org/gdb/wiki/BuildingOnDarwin

On 10.12 (Sierra) or later with SIP, you need to run this:

echo “set startup-with-shell off” >> ~/.gdbinit