Define a .clang-format file for the project

Each of these statements has been reviewed but
not all of them are obvious.

Also add a pre-commit config to easily check the
formatting.

Change-Id: I40f6af10c5ee2f5aed4185d783fc622a2e3c19ff
Signed-off-by: Frank Lichtenheld <frank@lichtenheld.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20250803150143.3878-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg32484.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

Author: flichtenheld

.clang-format

@@ -0,0 +1,51 @@
+---
+BasedOnStyle: Mozilla
+AccessModifierOffset: '-4'
+AlignAfterOpenBracket: Align
+AlignConsecutiveMacros:
+  Enabled: true
+  AcrossEmptyLines: false
+  AcrossComments: true
+AlignEscapedNewlines: Left
+AlignOperands: true
+AlignTrailingComments:
+  Kind: Always
+  OverEmptyLines: 1
+AllowAllParametersOfDeclarationOnNextLine: true
+AllowShortBlocksOnASingleLine: Never
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: Never
+AllowShortLoopsOnASingleLine: false
+BinPackArguments: true
+BinPackParameters: true
+BreakAfterReturnType: AllDefinitions
+BreakBeforeBinaryOperators: NonAssignment
+BreakBeforeBraces: Allman
+BreakBeforeTernaryOperators: true
+BreakStringLiterals: false
+ColumnLimit: '100'
+ContinuationIndentWidth: '4'
+DerivePointerAlignment: false
+IndentCaseLabels: true
+IndentGotoLabels: false
+IndentWidth: '4'
+IndentWrappedFunctionNames: false
+KeepEmptyLinesAtTheStartOfBlocks: false
+MaxEmptyLinesToKeep: '2'
+PointerAlignment: Right
+ReflowComments: true
+SortIncludes: false
+SpaceAfterCStyleCast: false
+SpaceBeforeAssignmentOperators: true
+SpaceBeforeParens: ControlStatements
+SpacesBeforeTrailingComments: '2'
+SpacesInParens: Never
+TabWidth: '4'
+TypeNames: [DWORD]
+UseTab: Never
+WhitespaceSensitiveMacros: [_STRINGIFY]
+---
+Language: C
+---
+Language: Cpp

.pre-commit-config.yaml

@@ -0,0 +1,8 @@
+repos:
+  - repo: https://github.com/pre-commit/mirrors-clang-format
+    rev: 'v20.1.0'
+    hooks:
+      - id: clang-format
+        files: \.[ch]$
+        # preserve upstream formatting
+        exclude: ^(src/compat/compat-lz4\.[ch]|src/openvpn/ovpn_dco_(linux|win)\.h)$