it's giving me this now
```
riscv64-unknown-elf-ld: framebuffer.o: in function `framebuffer_mmcm_write':
/home/paul/projects/fpga/litex/linux-on-litex-vexriscv/emulator/framebuffer.c:27: undefined reference to `framebuffer_driver_clocking_mmcm_adr_write'
riscv64-unknown-elf-ld: /home/paul/projects/fpga/litex/linux-on-litex-vexriscv/emulator/framebuffer.c:28: undefined reference to `framebuffer_driver_clocking_mmcm_dat_w_write'
riscv64-unknown-elf-ld: /home/paul/projects/fpga/litex/linux-on-litex-vexriscv/emulator/framebuffer.c:29: undefined reference to `framebuffer_driver_clocking_mmcm_write_write'
riscv64-unknown-elf-ld: /home/paul/projects/fpga/litex/linux-on-litex-vexriscv/emulator/framebuffer.c:30: undefined reference to `framebuffer_driver_clocking_mmcm_drdy_read'
make: *** [Makefile:19: emulator.elf] Error 1
```