wgpu: Add x11 device detection #386

	name: Check
	on: [push, pull_request]
	jobs:
	widget:
	runs-on: ubuntu-latest
	steps:
	- uses: hecrj/setup-rust-action@v1
	- uses: actions/checkout@master
	- name: Check standalone `iced_widget` crate
	run: cargo check --package iced_widget --features image,svg,canvas

	wasm:
	runs-on: ubuntu-latest
	env:
	RUSTFLAGS: --cfg=web_sys_unstable_apis
	steps:
	- uses: hecrj/setup-rust-action@v1
	with:
	rust-version: stable
	targets: wasm32-unknown-unknown
	- uses: actions/checkout@master
	- name: Run checks
	run: cargo check --package iced --target wasm32-unknown-unknown
	- name: Check compilation of `tour` example
	run: cargo build --package tour --target wasm32-unknown-unknown
	- name: Check compilation of `todos` example
	run: cargo build --package todos --target wasm32-unknown-unknown
	- name: Check compilation of `integration` example
	run: cargo build --package integration --target wasm32-unknown-unknown

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