Squashed 'libs/cli11/' content from commit dcbcb47

git-subtree-dir: libs/cli11
git-subtree-split: dcbcb4721dda5dab0a56d9faaaee50e6a30f7758

scripts/check_style_docker.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env sh
+
+# Also good but untagged: CLANG_FORMAT=unibeautify/clang-format
+# This might provide more control in the future: silkeh/clang:8 (etc)
+CLANG_FORMAT=saschpe/clang-format:5.0.1
+
+set -evx
+
+docker run --rm ${CLANG_FORMAT} --version
+docker run --rm --user $(id -u):$(id -g) -v "$(pwd)":/workdir -w /workdir ${CLANG_FORMAT} -style=file -sort-includes -i $(git ls-files -- '*.cpp' '*.hpp')
+
+git diff --exit-code --color
+
+set +evx