Merge branch 'bw/git-clang-format'

"make style" runs git-clang-format to help developers by pointing
out coding style issues.

* bw/git-clang-format:
  Makefile: add style build rule
  clang-format: outline the git project's coding style

.clang-format

@@ -0,0 +1,165 @@
+# Defaults
+
+# Use tabs whenever we need to fill whitespace that spans at least from one tab
+# stop to the next one.
+UseTab: Always
+TabWidth: 8
+IndentWidth: 8
+ContinuationIndentWidth: 8
+ColumnLimit: 80
+
+# C Language specifics
+Language: Cpp
+
+# Align parameters on the open bracket
+# someLongFunction(argument1,
+#                  argument2);
+AlignAfterOpenBracket: Align
+
+# Don't align consecutive assignments
+# int aaaa = 12;
+# int b = 14;
+AlignConsecutiveAssignments: false
+
+# Don't align consecutive declarations
+# int aaaa = 12;
+# double b = 3.14;
+AlignConsecutiveDeclarations: false
+
+# Align escaped newlines as far left as possible
+# #define A   \
+#   int aaaa; \
+#   int b;    \
+#   int cccccccc;
+AlignEscapedNewlines: Left
+
+# Align operands of binary and ternary expressions
+# int aaa = bbbbbbbbbbb +
+#           cccccc;
+AlignOperands: true
+
+# Don't align trailing comments
+# int a; // Comment a
+# int b = 2; // Comment b
+AlignTrailingComments: false
+
+# By default don't allow putting parameters onto the next line
+# myFunction(foo, bar, baz);
+AllowAllParametersOfDeclarationOnNextLine: false
+
+# Don't allow short braced statements to be on a single line
+# if (a)           not       if (a) return;
+#   return;
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+
+# By default don't add a line break after the return type of top-level functions
+# int foo();
+AlwaysBreakAfterReturnType: None
+
+# Pack as many parameters or arguments onto the same line as possible
+# int myFunction(int aaaaaaaaaaaa, int bbbbbbbb,
+#                int cccc);
+BinPackArguments: true
+BinPackParameters: true
+
+# Attach braces to surrounding context except break before braces on function
+# definitions.
+# void foo()
+# {
+#    if (true) {
+#    } else {
+#    }
+# };
+BreakBeforeBraces: Linux
+
+# Break after operators
+# int valuve = aaaaaaaaaaaaa +
+#              bbbbbb -
+#              ccccccccccc;
+BreakBeforeBinaryOperators: None
+BreakBeforeTernaryOperators: false
+
+# Don't break string literals
+BreakStringLiterals: false
+
+# Use the same indentation level as for the switch statement.
+# Switch statement body is always indented one level more than case labels.
+IndentCaseLabels: false
+
+# Don't indent a function definition or declaration if it is wrapped after the
+# type
+IndentWrappedFunctionNames: false
+
+# Align pointer to the right
+# int *a;
+PointerAlignment: Right
+
+# Don't insert a space after a cast
+# x = (int32)y;    not    x = (int32) y;
+SpaceAfterCStyleCast: false
+
+# Insert spaces before and after assignment operators
+# int a = 5;    not    int a=5;
+# a += 42;             a+=42;
+SpaceBeforeAssignmentOperators: true
+
+# Put a space before opening parentheses only after control statement keywords.
+# void f() {
+#   if (true) {
+#     f();
+#   }
+# }
+SpaceBeforeParens: ControlStatements
+
+# Don't insert spaces inside empty '()'
+SpaceInEmptyParentheses: false
+
+# The number of spaces before trailing line comments (// - comments).
+# This does not affect trailing block comments (/* - comments).
+SpacesBeforeTrailingComments: 1
+
+# Don't insert spaces in casts
+# x = (int32) y;    not    x = ( int32 ) y;
+SpacesInCStyleCastParentheses: false
+
+# Don't insert spaces inside container literals
+# var arr = [1, 2, 3];    not    var arr = [ 1, 2, 3 ];
+SpacesInContainerLiterals: false
+
+# Don't insert spaces after '(' or before ')'
+# f(arg);    not    f( arg );
+SpacesInParentheses: false
+
+# Don't insert spaces after '[' or before ']'
+# int a[5];    not    int a[ 5 ];
+SpacesInSquareBrackets: false
+
+# Insert a space after '{' and before '}' in struct initializers
+Cpp11BracedListStyle: false
+
+# A list of macros that should be interpreted as foreach loops instead of as
+# function calls.
+ForEachMacros: ['for_each_string_list_item']
+
+# The maximum number of consecutive empty lines to keep.
+MaxEmptyLinesToKeep: 1
+
+# No empty line at the start of a block.
+KeepEmptyLinesAtTheStartOfBlocks: false
+
+# Penalties
+# This decides what order things should be done if a line is too long
+PenaltyBreakAssignment: 100
+PenaltyBreakBeforeFirstCallParameter: 100
+PenaltyBreakComment: 100
+PenaltyBreakFirstLessLess: 0
+PenaltyBreakString: 100
+PenaltyExcessCharacter: 5
+PenaltyReturnTypeOnItsOwnLine: 0
+
+# Don't sort #include's
+SortIncludes: false

Makefile

@@ -2457,6 +2457,10 @@ $(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
 .PHONY: sparse $(SP_OBJ)
 sparse: $(SP_OBJ)
 
+.PHONY: style
+style:
+	git clang-format --style file --diff --extensions c,h
+
 check: common-cmds.h
 	@if sparse; \
 	then \