I've included the GCC version 8.2.0 for the raspberry pi 3, compiled by skarnet:
http://skarnet.org/toolchains

This toolchain will compile binaries that are supported by the pi 3 and upward models.
By default, the compiler in this toolchain will not look in the following directories:

/lib
/include
/usr/lib
/usr/include

So I've created a specs file (which I've added to the toolchain) using:
# gcc -dumpspecs > specs 
and edited it to look into the above directories.

# Location of the specs file: 
$(TOOLCHAIN)/lib/gcc/$(ARCH)-linux-musl/$(GCC_VERSION)/ 

so that it will look for the above directories on 
purpose and will save most people (including me) 
from linking nightmares.

I typically place the compiler in "/" for easy compiler access, followed by 
modification to $PATH. I also added /usr/local/bin directly after the toolchain $PATH
and then I added symlinks to ccache in /usr/local/bin. There's no need to make 
symlinks in /bin as gcc is now already in $PATH.

mkdir -p /usr/local/bin
ln -s /bin/ccache /usr/local/bin/cc
ln -s /bin/ccache /usr/local/bin/c++
ln -s /bin/ccache /usr/local/bin/gcc
ln -s /bin/ccache /usr/local/bin/g++