tools/compile_commands: use -Wno-unknown-warning-option

... instead of manual filtering

Some -Wwarning-type flags were removed because in combination with
-Werror they caused clang to fail when the warning type was unknown.
Rather than enumerating them (a manual process with the extra risk of
leaving warnings disabled longer than necessary), this adds
`-Wno-unknown-arning-option` which disables the warnings (that are
becoming erors through -Werror) raised when a warning's name is unknown.

dist/tools/compile_commands/compile_commands.py

@@ -228,6 +228,9 @@ def generate_module_compile_commands(path, state, args):
         except ValueError:
             pass
 
+    if args.clangd:
+        cdetails.cflags.append('-Wno-unknown-warning-option')
+
     c_extra_includes = []
     cxx_extra_includes = []
 
@@ -288,12 +291,13 @@ if __name__ == '__main__':
                         help='Drop the given flag, if present (repeatable)')
     parser.add_argument('--clangd', default=False, action='store_const', const=True,
                         help='Shorthand for --add-built-in-includes --add-libstdxx-includes ' +
-                             'and some CFLAG adjustments throughy --filter-out')
+                             'and some CFLAG adjustments throughy --filter-out, and ignores ' +
+                             'unknown warning flags')
     _args = parser.parse_args()
     if _args.clangd:
         _args.add_built_in_includes = True
         _args.add_libstdcxx_includes = True
-        _args.filter_out = ['-Wformat-truncation', '-Wformat-overflow', '-mno-thumb-interwork',
+        _args.filter_out = ['-mno-thumb-interwork',
                             # Only even included for versions of GCC that support it
                             '-malign-data=natural',
                             # Only supported starting with clang 11