Add patches for git v2.38, libpkgconf v1.9.0, and C++23 std::aligned_storage
    
    Fedora updates to git, libpkgconf, and GCC require some additional patches [1]
    to build2 to build and run correctly. These patches [2-4] are now upstreamed,
    and we apply them here.
    
     * bpkg-git-v2.38.patch: patch for git v2.38 dropping submodule--helper commands
     * build2.spec: use and apply new patches
     * libbuild2-cxx23-aligned_storage-deprecation.patch: patch for C++23
       std::aligned_storage deprecation
     * libbuild2-libpkgconf-error_handler-non-const-data.patch: patch for libpkgconf
       v1.9.0 changing the error handler function signature
    
    [1] https://lists.build2.org/archives/users/2023-March/001014.html
    [2] https://git.build2.org/cgit/bpkg/commit/?id=a97b12a027546b37f66d3e08064f92f5539cf79e
    [3] https://git.build2.org/cgit/build2/commit/?id=343d6e69e412166cfc21f268a51b692cb0201653
    [4] https://git.build2.org/cgit/build2/commit/?id=417be15231cb34a2e858d26b63406d1fb5535cb9