Klibc compilation is not working for at least 3 years because of
following error:
mdadm.h:1912:15: error: unknown type name 'sighandler_t'
It will have a conflict with le/be_to_cpu() functions family provided by
asm/byteorder.h which will be included with raid/md_p.h. Therefore we
need to remove support for it. Also, remove uclibc because it is not actively
maintained.
Remove klibc and uclibc targets from Makefile and special klibc code.
Targets can be removed safely because using CC is recommended.