Make it possible to use a relative path in command script import to the
location of the file being sourced. This allows the user to put Python
scripts next to LLDB command files and importing them without having to
specify an absolute path.
To enable this behavior pass `-c` to `command script import`. The
argument can only be used when sourcing the command from a file.
rdar://68310384
Differential revision: https://reviews.llvm.org/D89334
The Python script interpreter makes the current debugger, target,
process, thread and frame available to interactive scripting sessions
through convenience variables. This patch does the same for Lua.
Differential revision: https://reviews.llvm.org/D71801
Don't create a new lua state on every operation. Share a single state
across the lifetime of the script interpreter. Add simple locking to
prevent two threads from modifying the state concurrently.
