solver3: Avoid FTBFS with g++ 14.2 on arm{el,hf}

With an explicit {} initialization, g++ 14.2 on armhf and armel
seems to generate the default constructor for the vector too early,
or in the first place, outside of solver3.cc where the constructor
is defined.

Without {}, this compiles again.

    In file included from /usr/include/c++/14/vector:66,
                     from /<<PKGBUILDDIR>>/obj-arm-linux-gnueabihf/include/apt-pkg/cachefilter.h:14:
    /usr/include/c++/14/bits/stl_vector.h: In instantiation of ‘constexpr std::_Vector_base<_Tp, _Alloc>::~_Vector_base() [with _Tp = APT::Solver::Work; _Alloc = std::allocator<APT::Solver::Work>]’:
    /usr/include/c++/14/bits/stl_vector.h:531:7:   required from here
      531 |       vector() = default;
          |       ^~~~~~
    /usr/include/c++/14/bits/stl_vector.h:369:49: error: invalid use of incomplete type ‘struct APT::Solver::Work’
      369 |                       _M_impl._M_end_of_storage - _M_impl._M_start);
          |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
    In file included from /<<PKGBUILDDIR>>/apt-pkg/edsp.cc:22:
    /<<PKGBUILDDIR>>/obj-arm-linux-gnueabihf/include/apt-pkg/solver3.h:87:11: note: forward declaration of ‘struct APT::Solver::Work’
       87 |    struct Work;
          |           ^~~~
    /usr/include/c++/14/bits/stl_vector.h: In instantiation of ‘constexpr std::_Vector_base<_Tp, _Alloc>::~_Vector_base() [with _Tp = APT::Solver::Solved; _Alloc = std::allocator<APT::Solver::Solved>]’:
    /usr/include/c++/14/bits/stl_vector.h:531:7:   required from here
      531 |       vector() = default;
          |       ^~~~~~
    /usr/include/c++/14/bits/stl_vector.h:369:49: error: invalid use of incomplete type ‘struct APT::Solver::Solved’
      369 |                       _M_impl._M_end_of_storage - _M_impl._M_start);
          |                       ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
    /<<PKGBUILDDIR>>/obj-arm-linux-gnueabihf/include/apt-pkg/solver3.h:88:11: note: forward declaration of ‘struct APT::Solver::Solved’
       88 |    struct Solved;
          |           ^~~~~~

1 files changed, 2 insertions, 2 deletions

diff --git a/apt-pkg/solver3.h b/apt-pkg/solver3.h
index 2331af869..435c1c279 100644
--- a/apt-pkg/solver3.h
+++ b/apt-pkg/solver3.h
@@ -201,7 +201,7 @@ class Solver
    // and std::pop_heap() rather than a priority_queue because we need to
    // be able to iterate over the queued work and see if a choice would
    // invalidate any work.
-   heap<Work> work{};
+   heap<Work> work;
 
    // \brief Backlog of solved work.
    //
@@ -209,7 +209,7 @@ class Solver
    // here to revisit it later. This is similar to what MiniSAT calls the
    // trail; one distinction is that we have both literals and our work
    // queue to be concerned about
-   std::vector<Solved> solved{};
+   std::vector<Solved> solved;
 
    // \brief Propagation queue
    std::queue<Var> propQ;