[R-SIG-Mac] adding -Wall

[Kasper Daniel Hansen]

Hi

I am using the CRAN binary of R.

For package development I would like to compile with the -Wall flag.  
What is the best way to add this? Should I just edit
   R.Framework/Resources/ppc/etc/Makeconf
(I am on a G4), and add it to the CFLAGS, CXXFLAGS, FFLAGS variables.  
Or is there a better way, where I do not modify the files in the  
framework?

Btw: any reason why this is not enabled by default

Kasper