reference to `basic_ostream` is ambiguous when using libc++ and `#include <iostream>` first

[FeignClaims]

This library fails to compile with libc++ when #include <iostream> in front of #include <ut2>.

godbolt

/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:169:8: error: reference to 'basic_ostream' is ambiguous
  169 | extern basic_ostream<char, char_traits<char>> clog; // only used if defined
      |        ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:168:30: note: candidate found by name lookup is 'std::basic_ostream'
  168 | template<class, class> class basic_ostream;
      |                              ^
/opt/homebrew/opt/llvm/bin/../include/c++/v1/ostream:208:28: note: candidate found by name lookup is 'std::__1::basic_ostream'
  208 | class _LIBCPP_TEMPLATE_VIS basic_ostream : virtual public basic_ios<_CharT, _Traits> {
      |                            ^
In file included from /Users/feignclaims/code/cpp/cpp-practice/test/main.cpp:2:
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:169:28: error: reference to 'char_traits' is ambiguous
  169 | extern basic_ostream<char, char_traits<char>> clog; // only used if defined
      |                            ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:167:24: note: candidate found by name lookup is 'std::char_traits'
  167 | template<class> struct char_traits;
      |                        ^
/opt/homebrew/opt/llvm/bin/../include/c++/v1/__string/char_traits.h:83:92: note: candidate found by name lookup is 'std::__1::char_traits'
   83 |     "for a temporary period. It will be removed in LLVM 19, so please migrate off of it.") char_traits {
      |                                                                                            ^
In file included from /Users/feignclaims/code/cpp/cpp-practice/test/main.cpp:2:
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:180:39: error: reference to 'clog' is ambiguous
  180 |         static_assert(requires { std::clog << t; }, "[ERROR] No output supported: Consider #include <iostream> | ut::cfg<ut::override> = custom_cfg{} | #define UT_COMPILE_TIME_ONLY");
      |                                  ~~~~~^
/opt/homebrew/opt/llvm/bin/../include/c++/v1/iostream:57:42: note: candidate found by name lookup is 'std::__1::clog'
   57 | extern _LIBCPP_EXPORTED_FROM_ABI ostream clog;
      |                                          ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:169:47: note: candidate found by name lookup is 'std::clog'
  169 | extern basic_ostream<char, char_traits<char>> clog; // only used if defined
      |                                               ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:181:22: error: reference to 'clog' is ambiguous
  181 |         return (std::clog << t);
      |                 ~~~~~^
/opt/homebrew/opt/llvm/bin/../include/c++/v1/iostream:57:42: note: candidate found by name lookup is 'std::__1::clog'
   57 | extern _LIBCPP_EXPORTED_FROM_ABI ostream clog;
      |                                          ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:169:47: note: candidate found by name lookup is 'std::clog'
  169 | extern basic_ostream<char, char_traits<char>> clog; // only used if defined
      |                                               ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:181:22: error: unknown type name 'clog'
  181 |         return (std::clog << t);
      |                      ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:181:27: error: expected ')'
  181 |         return (std::clog << t);
      |                           ^
/Users/feignclaims/.conan2/p/b/boost44f8b84116680/p/include/ut2:181:16: note: to match this '('
  181 |         return (std::clog << t);
      |                ^
6 errors generated.