[Bug libstdc++/103381] New: [9/10/11/12 Regression] --enable-libstdcxx-allocator=bitmap doesn't build

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103381

            Bug ID: 103381
           Summary: [9/10/11/12 Regression]
                    --enable-libstdcxx-allocator=bitmap doesn't build
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org
  Target Milestone: ---

<ext/bitmap_allocator.h> includes <function> which includes <unordered_map> in
C++17 mode. If std::allocator is defined in terms of bitmap_allocator then you
get a circular reference and bootstrap fails.

Clearly nobody has tried to use --enable-libstdcxx-allocator=bitmap in several
years.