This reverts commit e772216e708937988c039420d2c559568f91ae27
(and fixup 7f6c878a2c035eb6325ab228d9bc2d257509d959).
The build is broken with gcc5 host compiler:
In file included from
from mlir/lib/Dialect/Utils/StructuredOpsUtils.cpp:9:
tools/mlir/include/mlir/IR/BuiltinAttributes.h.inc:424:57: error: type/value mismatch at argument 1 in template parameter list for 'template<class ItTy, class FuncTy, class FuncReturnTy> class llvm::mapped_iterator'
std::function<T(ptrdiff_t)>>;
^
tools/mlir/include/mlir/IR/BuiltinAttributes.h.inc:424:57: note: expected a type, got 'decltype (seq<ptrdiff_t>(0, 0))::const_iterator'