Import Linux kernel .clang-format with small modifications

.clang-format

@@ -0,0 +1,50 @@
+BasedOnStyle: LLVM
+IndentWidth: 8
+UseTab: Always
+BreakBeforeBraces: Linux
+AllowShortIfStatementsOnASingleLine: false
+IndentCaseLabels: false
+AlwaysBreakAfterReturnType: All
+Cpp11BracedListStyle: false
+ColumnLimit: 80
+AlignAfterOpenBracket: Align
+AlignConsecutiveDeclarations: true
+AlwaysBreakBeforeMultilineStrings: false
+BreakBeforeBinaryOperators: None
+BreakBeforeTernaryOperators: true
+AlignEscapedNewlines: Left
+DerivePointerAlignment: false
+PointerAlignment: Right
+IncludeBlocks: Regroup
+IncludeCategories:
+  - Regex:           '^<isc/'
+    Priority:        2
+  - Regex:           '^<dns/'
+    Priority:        3
+  - Regex:           '^<iscccc/'
+    Priority:        4
+  - Regex:           '^<isccfg/'
+    Priority:        5
+  - Regex:           '^<ns/'
+    Priority:        6
+  - Regex:           '^<bind9/)'
+    Priority:        7
+  - Regex:           '^(<[^/]*)/)'
+    Priority:        8
+  - Regex:           '<[[:alnum:].]+>'
+    Priority:        1
+  - Regex:           '".*"'
+    Priority:        9
+KeepEmptyLinesAtTheStartOfBlocks: false
+
+# Taken from git's rules
+PenaltyBreakAssignment: 10
+# PenaltyBreakBeforeFirstCallParameter: 30
+PenaltyBreakComment: 10
+PenaltyBreakFirstLessLess: 0
+PenaltyBreakString: 10
+PenaltyExcessCharacter: 100
+
+Standard: Cpp11
+
+ContinuationIndentWidth: 8

util/copyrights

@@ -1,3 +1,4 @@
+./.clang-format					X	2019,2020
 ./.gitlab-ci.yml				X	2018,2019,2020
 ./.uncrustify.cfg				X	2018,2019,2020
 ./CHANGES					X	2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019,2020

util/update_copyrights

@@ -521,10 +521,10 @@ foreach $file (keys %file_types) {
 			# Process leading white space.
 			# Remove 1-7 spaces followed by a tab into a single
 			# tab if at start of line or proceeded by tabs.
-			s/^(\t*) {1,7}\t/$1\t/ while (/^\t* {1,7}\t/);
+			# s/^(\t*) {1,7}\t/$1\t/ while (/^\t* {1,7}\t/);
 			# Convert 8 spaces into tabs if at start of line
 			# or preceeded by tabs.
-			s/^(\t*) {8}/$1\t/ while (/^\t* {8}/);
+			# s/^(\t*) {8}/$1\t/ while (/^\t* {8}/);
 			# Remove trailing white space.
 			s/[ \t]*$//;
 				$body = "$body$_";