> (.text+0x20): undefined reference to `main'
> collect2: ld returned 1 exit status
> make[2]: *** [wmluiltok] Error 1

That is indeed the same build error that I'm encountering.  When I
installed flex-devel the issue went away.

I'm guessing that the relevant flex library actually does define a main()
function and that when the devel package in installed the linker uses a
main function from the library itself.