Location of .H header files

[ib1yysguy]

I've installed AVR-Libc (I'm on a Mac), however I'm concerned about whether or not the compiler will find them. When you include it in the code, you type #include avr/io.h"

It installed them in the usr/local/avr/include folder. However, all the rest of the include files one generally calls up are in the staright up /include/ directory.

How the heck does the compiler know where to draw the header from?