altering source and compiling coreutils

[GVK]

Hello,
	I downloaded the tar-ball of coreutils-5.2.1. I messed around with 
"printf" sourcecode (coreutils-5.2.1/src/printf.c) and fixed a 
bug(feature ?). "printf "%c" 65" is supposed to print 'A'(ie, printf 
should really mimic C's printf), but it prints '6'. So, I kinda changed 
it. The problem is, I don't know how to edit a Makefile. Now, when I run
"make" in coreutils directory, some executables are created in "src" 
directory. The printf executable in src directory is working as 
expected. But when I do a "make install" or copy the executable to 
/usr/bin, it's not working. Any suggestions?

regards,
GVK