How to use linux path in eclipse cdt?

Question

I wrote in my Makefile:

GCC := i386-elf-gcc

and use it to build my project.

But when I click my 'build' button, the eclipse cdt console gets an error:

make all 
make: i386-elf-gcc: No such file or directory
make: *** [boot/bootmain.o] Error 1

I use mac os. and the path of i386-elf-gcc:

zsh> which i386-elf-gcc                                           
/usr/local/bin/i386-elf-gcc

In my /etc/paths there has /usr/local/bin. So I wonder how to fix this problem?? Thank you!