GTiff: Avoid value-initialization of vector of forward declared class

[nilason]

What does this PR do?

Trigger default-initialisation instead of value-initialisation of vector of forward declared class (in frmts/gtiff/gtiffdataset.h).

Addresses "invalid application of 'sizeof' to an incomplete type 'GTiffJPEGOverviewDS'" compiler error on macOS 12 and earlier (with AppleClang 13 and earlier):

In file included from /opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/frmts/gtiff/cogdriver.cpp:15:
In file included from /opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/gcore/gdalalgorithm.h:16:
In file included from /opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/gcore/gdalalgorithm_c.h:19:
In file included from /opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/gcore/gdal.h:30:
In file included from /opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/port/cpl_error.h:395:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/memory:682:
In file included from /Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/shared_ptr.h:25:
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/unique_ptr.h:53:19: error: invalid application of 'sizeof' to an incomplete type 'GTiffJPEGOverviewDS'
    static_assert(sizeof(_Tp) > 0,
                  ^~~~~~~~~~~
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/unique_ptr.h:318:7: note: in instantiation of member function 'std::default_delete<GTiffJPEGOverviewDS>::operator()' requested here
      __ptr_.second()(__tmp);
      ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/unique_ptr.h:272:19: note: in instantiation of member function 'std::unique_ptr<GTiffJPEGOverviewDS>::reset' requested here
  ~unique_ptr() { reset(); }
                  ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/allocator.h:159:15: note: in instantiation of member function 'std::unique_ptr<GTiffJPEGOverviewDS>::~unique_ptr' requested here
        __p->~_Tp();
              ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/__memory/allocator_traits.h:309:13: note: in instantiation of member function 'std::allocator<std::unique_ptr<GTiffJPEGOverviewDS>>::destroy' requested here
        __a.destroy(__p);
            ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/vector:450:25: note: in instantiation of function template specialization 'std::allocator_traits<std::allocator<std::unique_ptr<GTiffJPEGOverviewDS>>>::destroy<std::unique_ptr<GTiffJPEGOverviewDS>, void>' requested here
        __alloc_traits::destroy(__alloc(), _VSTD::__to_address(--__soon_to_be_end));
                        ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/vector:374:29: note: in instantiation of member function 'std::__vector_base<std::unique_ptr<GTiffJPEGOverviewDS>, std::allocator<std::unique_ptr<GTiffJPEGOverviewDS>>>::__destruct_at_end' requested here
    void clear() _NOEXCEPT {__destruct_at_end(__begin_);}
                            ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/vector:487:9: note: in instantiation of member function 'std::__vector_base<std::unique_ptr<GTiffJPEGOverviewDS>, std::allocator<std::unique_ptr<GTiffJPEGOverviewDS>>>::clear' requested here
        clear();
        ^
/Library/Developer/CommandLineTools/SDKs/MacOSX12.sdk/usr/include/c++/v1/vector:519:5: note: in instantiation of member function 'std::__vector_base<std::unique_ptr<GTiffJPEGOverviewDS>, std::allocator<std::unique_ptr<GTiffJPEGOverviewDS>>>::~__vector_base' requested here
    vector() _NOEXCEPT_(is_nothrow_default_constructible<allocator_type>::value)
    ^
/opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/frmts/gtiff/gtiffdataset.h:136:74: note: in instantiation of member function 'std::vector<std::unique_ptr<GTiffJPEGOverviewDS>>::vector' requested here
    std::vector<std::unique_ptr<GTiffJPEGOverviewDS>> m_apoJPEGOverviewDS{};
                                                                         ^
/opt/local/var/macports/build/gdal-ab2406e0/work/gdal-3.13.0/frmts/gtiff/gtiffdataset.h:43:7: note: forward declaration of 'GTiffJPEGOverviewDS'
class GTiffJPEGOverviewDS;
      ^

This wasn't an issue on macOS 13 and newer, I can't test this fix on the failing platform but it compiles fine on macOS 26. I noticed this failure on MacPorts' build logs.

What are related issues/pull requests?

AI tool usage

• AI (Y-a-t-il-un-Copilot-dans-l'avion, Chat-j'ai-pété, Jean-Claude Dusse or something similar) supported my development of this PR. See our policy about AI tool use. Use of AI tools must be indicated.

Tasklist

• Make sure code is correctly formatted (cf pre-commit configuration)
• Add test case(s)
• Add documentation
• Updated Python API documentation (swig/include/python/docs/)
• Review
• Adjust for comments
• All CI builds and checks have passed
• ADD YOUR TASKS HERE

Environment

Provide environment details, if relevant:

• OS: macOS 12.7.6
• Compiler: AppleClang 13.1.6.13160021

[nilason]

Oh, this apparently needs another approach:

/home/runner/work/gdal/gdal/frmts/gtiff/gtiffdataset.cpp:72:1: error: 'GTiffDataset::m_apoJPEGOverviewDS' should be initialized in the member initialization list [-Werror=effc++]
72 | GTiffDataset::GTiffDataset()
| ^~~~~~~~~~~~
/home/runner/work/gdal/gdal/frmts/gtiff/gtiffdataset.cpp:72:1: error: 'GTiffDataset::m_apoJPEGOverviewDSOld' should be initialized in the member initialization list [-Werror=effc++]

[nilason]

Now I believe it should be ok.