Ruby

Setup clang format for C code #6776

Job	Run time
valgrind	51m 54s
C99_compile (3.4)	57s
test (3.1, test)	2m 48s
C99_compile (head)	1m 13s
test (3.2, test)	2m 43s
test (3.3, test)	3m 22s
test (3.4, test)	3m 3s
test (head, test)	3m 18s
test (head, stdlib_test rubocop)	3m 5s
test (3.4, stdlib_test)	2m 15s
test (3.4, test, --enable-frozen-string-literal)	2m 51s
test (3.4, stdlib_test, --enable-frozen-string-literal)	2m 15s
test (3.4, rubocop validate test_doc build test_generate_stdlib raap)	2m 42s
test (3.4, typecheck_test)	1m 8s
	1h 23m 34s

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