I was curious so I did make allmodconfig (I'm on 64-bit x86) and 'made bzImage modules' and counted lines of c/asm source with a corresponding .o file, all the header files and Makefile/Kconfig lines and got:

headers: 3011226

c/asm source: 8264404

generated .mod.c: 8414151

makefile/kconfig: 2032728

total 21722509

(Again, this is v3.10) (I also included the generated .mod.c files) https://gist.github.com/fragmede/8782876