5459fa132a
<ext/bitmap_allocator.h> includes <function>, and since C++17 that includes <unordered_map>. If std::allocator is defined in terms of __gnu_cxx::bitmap_allocator then you get a circular reference and bootstrap fails when compiling src/c++17/*.cc. libstdc++-v3/ChangeLog: PR libstdc++/103381 * include/ext/bitmap_allocator.h: Include <bits/stl_function.h> instead of <functional>.