Modifying the std C libraries

[Rick Mann <rmann@xxxxxxxxxxxxxxx>]

We've got an xscale-elf cross compiler built using binutils, gcc 4,  
and newlib. It all seems to work reasonably well. Now we've reached a  
point where we must strip out all uncalled source code from newlib,  
and rebuild that.

I tried the experiment of building a new newlib with the xscale-elf  
tools, which worked fine, and then making a simple test program that  
linked against printf(), then removing printf() and rebuilding newlib  
and relinking. I would expect it to fail, but it doesn't.

I wonder if GCC is implicitly linking against the newlib that was  
built with it, rather than my new newlib (even though i specify -I and  
-L and -lc).

How can I get GCC to ignore the stuff it would normally implicitly  
link against and instead link against a very specific version of the  
runtime libs?

TIA,
--
Rick