How can I globally set the PATH environment variable in VS Code?

If you only need the $PATH to be set in the integrated terminal, you can use VS Code’s terminal.integrated.env.<platform> variable (added in version 1.15). Press Cmd+Shift+P (or Ctrl+Shift+P) and search for “Preferences: Open Settings (JSON)”. Then add the following entry to the settings file:

"terminal.integrated.env.osx": {
  "PATH": "...:/usr/bin:/bin:..."
}

(Replace .osx with .linux or .windows as needed.)

To see your system’s $PATH, type echo "$PATH" in Terminal.app, and copy and paste it into the settings snippet above.

As for having the $PATH available everwhere in VS Code, so that it will
be used by extensions that call binaries, the only workaround I’ve found so far is this:

1. Configure your shell (bash by default) to have the $PATH you want. For example, my ~/.bash_profile has the following line:

    PATH="$PATH:$HOME/bin"
   

2. In VS Code, press ⇧⌘P and type install 'code' command if you haven’t done so before.

3. Quit VS Code.

4. Launch VS Code not by clicking the icon in the dock or in Launchpad, but by opening Terminal.app and typing code. Your newly set path will be active in VS Code until you quit it.

5. If VS Code restarts, for example due to an upgrade, the $PATH will reset to the system default. In that case, quit VS Code and re-launch it by typing code.

Update: VS Code on Mac and Linux now apparently tries to automatically resolve the shell environment when it is started by clicking the icon (rather than via code). It does this by temporarily starting a shell and reading the environment variables. I haven’t tested this though.