Add support for clang for c

ale_linters/c/clang.vim

@@ -0,0 +1,20 @@
+" Author: Masahiro H https://github.com/mshr-h
+" Description: clang linter for c files
+
+" Set this option to change the Clang options for warnings for C.
+if !exists('g:ale_c_clang_options')
+    " let g:ale_c_clang_options = '-Wall'
+    " let g:ale_c_clang_options = '-std=c99 -Wall'
+    " c11 compatible
+    let g:ale_c_clang_options = '-std=c11 -Wall'
+endif
+
+call ale#linter#Define('c', {
+\   'name': 'clang',
+\   'output_stream': 'stderr',
+\   'executable': 'clang',
+\   'command': 'clang -S -x c -fsyntax-only '
+\       . g:ale_c_clang_options
+\       . ' -',
+\   'callback': 'ale#handlers#HandleGCCFormat',
+\})