I am asking here because I have no idea where to find any information about this problem. If you could recommend me a book or an article about it, I would be pleased.
Where can I find any information about correlation between Linux kernel and GLIBC's version? I know that, the kernel itself contains implementation of libc's functions, but I do not know, how they are delivered to it.
For example: Recently I had to build the kernel for an old PowerPC processor. It came with libc's dynamic library files in version 2.3.6 out-of-the-box. In /lib/ path there are files with names like librt.so-2.3.6.
What is the simplest way to update this lib to a newer version? Is it possible to configure kernel's build system to make it generating uImage file with a newer GLIBC version or an alternative one (ex. EGLIBC)?
There is little correlation, the same kernel should work with a wide range of glibc versions, and viceversa. The library finds out what the kernel handles, and uses that. For the gory details of what has changed in glibc (this is what you interact with, including support for new kernel features), you should look at the upstream changelog. For new features in the Linux kernel, perhaps the best source are the periodical "What's new in..." articles the kernel section of LWN