> (.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.