Suppress 'anon_bitfield_qualifiers' errors

Those errors are present in the CMSIS-Atmel package, and makes the
language server produce other bogus errors as a consquence of parse
failure of header files.

See arduino/arduino-ide#307
See arduino/arduino-ide#112

Author: cmaglie

Diff for: ls/ls.go

@@ -136,6 +136,14 @@ func NewINOLanguageServer(stdin io.Reader, stdout io.Writer, config *Config) *IN
 		ls.buildSketchRoot = ls.buildPath.Join("sketch")
 	}
 
+	clangdConf := ls.buildSketchRoot.Join(".clangd")
+	if err := clangdConf.WriteFile([]byte(`
+Diagnostics:
+	Suppress: [anon_bitfield_qualifiers]
+`)); err != nil {
+		logger.Logf("Error writing clangd configuration: %s", err)
+	}
+
 	logger.Logf("Initial board configuration: %s", ls.config.Fqbn)
 	logger.Logf("Language server build path: %s", ls.buildPath)
 	logger.Logf("Language server build sketch root: %s", ls.buildSketchRoot)