The "old" compiler is for compiling the base system and xenocara. There are gcc4 and clang packages available. Some packages are build using those more modern compilers.
I.e. Chromium is build with clang (3.8) if I'm not mistaken.
I.e. Chromium is build with clang (3.8) if I'm not mistaken.
This means they rely on "old" compilers to compile "old" C code from the base.