[libc++][test] Mark throw_format_error as noreturn.

This fixes and GCC error. This was tested in D135787.

diff --git a/libcxx/test/support/format.functions.common.h b/libcxx/test/support/format.functions.common.h
index e5f6bbb..e979a20 100644 (file)
--- a/libcxx/test/support/format.functions.common.h
+++ b/libcxx/test/support/format.functions.common.h
@@ -134,11 +134,10 @@ struct std::formatter<status, CharT> {
   }
 
 private:
-  void throw_format_error(const char* s) const {
+  [[noreturn]] void throw_format_error([[maybe_unused]] const char* s) const {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     throw std::format_error(s);
 #else
-    (void)s;
     std::abort();
 #endif
   }