Add support for debugging C++ from Positron

See posit-dev/positron#4534
On Linux I also needed to run
sudo sysctl -w kernel.yama.ptrace_scope=0

.Rbuildignore

@@ -21,3 +21,5 @@
 ^\.cache$
 ^compile_commands\.json$
 ^touchstone$
+^\.vscode$
+^debug$

.vscode/launch.json

@@ -0,0 +1,28 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "(lldb) Launch R",
+      "type": "lldb",
+      "request": "launch",
+      "program": "/Library/Frameworks/R.framework/Resources/bin/exec/R",
+      "args": [
+        "--vanilla",
+        "-e",
+        "source('debug/debug.R')"
+      ],
+      "env": {
+        "R_HOME" : "/Library/Frameworks/R.framework/Resources"
+      },
+      "terminal": "console",
+      "stopOnEntry": false
+    },
+    {
+      "name": "(lldb) Attach to R",
+      "type": "lldb",
+      "request": "attach",
+      "pid": "${command:pickMyProcess}",
+      "stopOnEntry": false
+    }
+  ]
+}

debug/debug.R

@@ -0,0 +1,7 @@
+devtools::clean_dll()
+devtools::load_all()
+Sys.getpid()
+
+dqrng::dqrunif(10)
+
+dqrng::dqRNGkind("pcg64")