[Bug c++/86550] Lambda parsing allows arbitrary types in decl-specifier-seq

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86550

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 44403
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=44403&action=edit
gcc9-pr86550.patch

Untested fix.