Add clang-formatting

Author: Zifzaf

.clang-format

@@ -0,0 +1,14 @@
+---
+Language: Cpp
+BasedOnStyle: LLVM
+IndentWidth: 4
+AlignAfterOpenBracket: Align
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+IndentCaseLabels: true
+SpacesBeforeTrailingComments: 2
+PointerAlignment: Left
+AlignEscapedNewlines: Left
+ForEachMacros: ['TEST_GROUP', 'TEST']
+...

.gitlab-ci.yml

@@ -19,6 +19,8 @@ syntax_check:
     # For performance and stability reasons, use offline installation.
     - pip install --no-index --find-links=/pip editorconfig-checker
     - pip install flake8
+    - apt-get update && apt-get install -yq clang-format-6.0
   script:
     - editorconfig-checker
     - flake8
+    - find . -type f -iregex ".*\.\(c\|h\|cpp\|ino\)" -exec clang-format-6.0 -i -style=file {} \;