[Bug libstdc++/123908] [16 regression] Undefined reference to std::__get_once_call()

[lh_mouse at 126 dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123908

--- Comment #15 from LIU Hao <lh_mouse at 126 dot com> ---
Created attachment 63645
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=63645&action=edit
diff of symbols

Diff'ing your DLL with my working shows a lot of missing symbols:

   llvm-readobj --coff-exports /mingw64/bin/libstdc++-6.dll  | sed -En 's/^ 
Name: (.*)$/\1/p' > good.txt
   llvm-readobj --coff-exports libstdc++-6.dll  | sed -En 's/^  Name:
(.*)$/\1/p' > bad.txt
   git diff --no-index good.txt bad.txt > symbols.diff

And as you can see, `_ZSt15__get_once_callv
` is just one of them.