I finished with LFS 7.2, and started with BLFS. All I do in BLFS is install X Windows System and KDE, along with all the required and recommended packages and software. I need to install Udev Extras (from systemd), but I alread installed Udev in LFS, and my Udev version is 188. Here is the output of what I get while installing Udev Extras (from systemd).

root [ /sources ]# tar -Jxf systemd-188.tar.xz
root [ /sources ]# cd systemd-188
root [ /sources/systemd-188 ]# tar -xf ../udev-lfs-188-3.tar.bz2
root [ /sources/systemd-188 ]# make -f udev-lfs-188/Makefile.lfs keymap
CC src/shared/log.c
Assembler messages:
Fatal error: can't create build/log.o: No such file or directory
cc1: fatal error: cfg.h: No such file or directory
compilation terminated.
make: *** [build/log.o] Error 2

If I try to check the output of my udevadm I get the following:
root [ /sources/systemd-188 ]# /sbin/udevadm --version
188

What can be the problem, and how can I solve it?

I had to do this first:

Thanks that solved the problem!