Does not build with gcc-15

Description:

Cannot be built with gcc-15

This is a part of the very long error:

In file included from /usr/include/c++/15.1.1/bits/move.h:37,
                 from /usr/include/c++/15.1.1/bits/exception_ptr.h:41,
                 from /usr/include/c++/15.1.1/exception:168,
                 from /usr/include/c++/15.1.1/ios:43,
                 from /usr/include/c++/15.1.1/bits/ostream.h:43,
                 from /usr/include/c++/15.1.1/ostream:42,
                 from /usr/include/c++/15.1.1/iostream:43,
                 from ../c++/etip.h:351,
                 from ../c++/cursesw.h:52,
                 from ../c++/cursesp.h:41,
                 from ../c++/cursesf.h:41,
                 from ../c++/cursesf.cc:36:
/usr/include/c++/15.1.1/type_traits:360:12: error: redefinition of ‘struct std::__is_integral_helper<unsigned char>’
  360 |     struct __is_integral_helper<unsigned char>
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/15.1.1/type_traits:348:12: note: previous definition of ‘struct std::__is_integral_helper<unsigned char>’
  348 |     struct __is_integral_helper<bool>
      |            ^~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/15.1.1/bits/exception_ptr.h:168:7: error: defaulted ‘NCURSES_BOOL std::__exception_ptr::operator==(const exception_ptr&, const exception_ptr&)’ must return ‘bool’
  168 |       operator==(const exception_ptr&, const exception_ptr&) noexcept = default;
      |       ^~~~~~~~
/usr/include/c++/15.1.1/bits/exception_ptr.h: In member function ‘std::__exception_ptr::exception_ptr::operator NCURSES_BOOL() const’:
/usr/include/c++/15.1.1/bits/exception_ptr.h:162:16: error: invalid conversion from ‘void*’ to ‘NCURSES_BOOL’ {aka ‘unsigned char’} [-fpermissive]
  162 |       { return _M_exception_object; }
      |                ^~~~~~~~~~~~~~~~~~~
      |                |
      |                void*
In file included from /usr/include/c++/15.1.1/exception:169:
/usr/include/c++/15.1.1/bits/nested_exception.h: In member function ‘void std::nested_exception::rethrow_nested() const’:
/usr/include/c++/15.1.1/bits/nested_exception.h:78:11: error: invalid user-defined conversion from ‘const std::__exception_ptr::exception_ptr’ to ‘bool’ [-fpermissive]
   78 |       if (_M_ptr)
      |           ^~~~~~
/usr/include/c++/15.1.1/bits/exception_ptr.h:161:16: note: candidate is: ‘std::__exception_ptr::exception_ptr::operator NCURSES_BOOL() const’ (near match)
  161 |       explicit operator bool() const noexcept
      |                ^~~~~~~~