cstyle: ignore old non-POSIX types in macro invocations

In code generation macros, we often use names like `uint` when
constructing handler functions. These are not being used as types, so
exclude them from the admonishment to use POSIX type names.

Sponsored-by: https://despairlabs.com/sponsor/
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes #16840

scripts/cstyle.pl

@@ -695,10 +695,13 @@ ($$)
 			err("unary * followed by space");
 		}
 	}
-	if ($check_posix_types) {
+	if ($check_posix_types && !$in_macro_call) {
 		# try to detect old non-POSIX types.
 		# POSIX requires all non-standard typedefs to end in _t,
 		# but historically these have been used.
+		#
+		# We don't check inside macro invocations because macros have
+		# legitmate uses for these names in function generators.
 		if (/\b(unchar|ushort|uint|ulong|u_int|u_short|u_long|u_char|quad)\b/) {
 			err("non-POSIX typedef $1 used: use $old2posix{$1} instead");
 		}