libgcc9/gcc9: build fails with clang-9.0 during build of gencondmd: Undefined symbols for architecture x86_64: "ix86_binary_operator_ok(rtx_code, machine_mode, rtx_def**)"

[kencu (Ken)]

During the build of gcc9 with clang-9.0, the build fails with the error(s) as above.

Building gcc9 with clang-8.0 succeeds, but there are many warnings at the same point in the build.

Obviously will need to be reported upstream, but in the meantime, building gcc9 with clang-9.0 is no bueno.

I don't know yet about gcc 8,7,6,5, or 4