inspector: restore --debug-brk alias

--inspect-brk didn't exist prior to 7.6.0, and --debug-brk doesn't exist
after nodejs#12197, leaving no consistent
way to start node with inspector activated and breaking on first line.
Add --debug-brk back in as an undocumented option until 7.x is no longer
supported.

Fixes: nodejs#12364

src/node_debug_options.cc

@@ -77,16 +77,17 @@ bool DebugOptions::ParseOption(const std::string& option) {
  argument = option.substr(pos + 1);
  }
 
+ // Note that --debug-port and --debug-brk are undocumented, but to be
+ // supported until 7.x is no longer supported, not even in LTS (see #12364).
  if (option_name == "--inspect") {
  enable_inspector = true;
- } else if (option_name == "--inspect-brk") {
+ } else if (option_name == "--inspect-brk" || option_name == "--debug-brk") {
+ debugger_enabled_ = true;
  enable_inspector = true;
  wait_connect_ = true;
- } else if ((option_name != "--debug-port" &&
- option_name != "--inspect-port") ||
- !has_argument) {
- // only other valid possibility is --inspect-port,
- // which requires an argument
+ } else if (option_name == "--inspect-port" || option_name == "--debug-port") {
+ if (!has_argument) return false;
+ } else {
  return false;
  }
 

src/node_debug_options.h

@@ -27,7 +27,7 @@ class DebugOptions {
 #if HAVE_INSPECTOR
  bool inspector_enabled_;
 #endif // HAVE_INSPECTOR
- bool wait_connect_;
+ bool wait_connect_; // --inspect-brk
  bool http_enabled_;
  std::string host_name_;
  int port_;