I think you'll get a lot better responses if you try things and ask specific questions when you have problems. Download the code. See how it compiles. That will answer many of your questions.
There are some functions in the source code of coreboot version 4 which have not defined any where like pci_get_dev(), What does it mean? Is Coreboot-V4 is incomplete?
Is coreboot using some library functions of Linux distribution? I saw some header files like <stdio.h> , where are their definitions?
Is it compulsory for Coreboot to be linked with a Linux kernel?
Do we use GCC of the Linux distribution or Coreboot source code has a separate GCC? Can Coreboot be used with Linux kernel 2.6.34? Can GCC make an absolute compiled code, I mean the result code do not be relocatable. Please write a GCC command to make a absolute binary.
You can use your distribution's version of gcc or the one supplied in the tree in util/crossgcc. You can run make -n or look through the make files to see how it's done.
What is the first function of the Coreboot code? Where is it?
There is a little assembly to get things set up, then romstage.c for your specific mainboard is the place to look.
Thanks, Myles