I have been trying to compile the kernel version 126.96.36.199 in fedora 14 32-bit which already has 2.6.35 version.Need multiple kernels for a project :)
Yeah,so when i run the make oldconfig command,i get the issue that says ::: "Makefile:412: *** mixed implicit and normal rules. Stop."
I somehow rectified that and when i run the same command again, ::: "Makefile:1441: *** mixed implicit and normal rules. Stop."
Use virtual machines to install/test new kernels first? I don't think that a 2.6.21 kernel will work with FC14 as there are SERIOUS deltas between the 2.6.2x and 2.6.3x kernels which require different user-side application versions to run. IE, won't work unless you also downgrade just about everything else on the system!
FWIW, I do use multiple kernels as well to test stuff out, and they are alternatives in my grub menu, so I can boot which I prefer, but they are generally just a point difference or two from what is the default for the system. Example, I run a Red Hat Enterprise Linux clone, Scientific Linux, with the current 2.6.32-279.19.1 kernel, but I also sometimes run earlier versions of the 2.6.32 kernel, such as 2.6.32-202, etc. As I suggested before, when I want to vett kernels that are very different (older or newer), then I install an appropriate base system in a virtual machine and start with that. VirtualBox (free/open source from Sun/Oracle) has worked well for me for about 6 years now. I use it on both Linux and Windows hosts.