Ccache

ccache is a program that caches compilation and makes recompilation very fast (5 to 10 times faster). The way you use it is you call

ccache path/to/compile compiler_args

We set this up by changing the compiler to be the first argument of the compiler, and then the compiler to being ccache. We do this in both our toolchain files, since any modifications to the compiler outside the toolchain gets reverted back!