Stock Kernel Source re-compile

Hi All, Assume I load up a Dell PE 1650 with SuSE 8.0 along with kernel source. Now, what I want to do is modify exactly two lines in /usr/src/linux/include/linux/fs.h to give me a larger open file per process limit (default is 1024). However, when I do this, what do I need to do to ensure proper recompile and a bootable system with the stock /lib/modules? I can get it work if I unpack raw source from kernel.org, so what am I not seeing here? feeling stupid today :) -Bill