Hyper doesn't set the environment variable $WINDOWID

• I am on the latest Hyper.app version
• I have searched the issues of this repo and believe that this is not a duplicate
• OS version and name: Arch Linux
• Hyper.app version: 1.3.3
• Link of a Gist with the contents of your .hyper.js: No changes made to default config. (N/A)
• Relevant information from devtools: N/A
• The issue is reproducible in vanilla Hyper.app: Yes

Issue

hyper doesn't seem to be setting the environment variable $WINDOWID. Various applications on Linux use this to function, namely w3m-img (Terminal image viewer) which uses the variable to identify which window to display the images in.

Without this environment variable being set w3m-img fails to locate the window to display images in and fails to function entirely.

All of the other terminal emulators I've tried set this variable from minimalist terminal emulators like st and alacritty to more featureful terminal emulators like xterm, URxvt and the VTE family (GNOME-terminal, XFCE4-terminal, Konsole, termite.)

The point I'm trying to get across is that I haven't found a terminal emulator that doesn't set this.

More information:

• https://github.com/jwilm/alacritty/issues/471
• https://github.com/jwilm/alacritty/pull/586

Reproduce the issue on Arch Linux with Hyper 1.3.3 and w3m-img, then compare Hyper's behavior with the terminal emulators listed in the report. Done means Hyper sets WINDOWID for its Linux terminal window so w3m-img can locate and display images; no source file or test is named in the issue.