INSTALL instructions of linux bindist says "make install" while it should be "sudo make install"
INSTALL of https://downloads.haskell.org/~ghc/8.8.3/ghc-8.8.3-x86_64-deb9-linux.tar.xz (and probably others) says
The default installation directory is /usr/local
...
Now run:
make install
This will fail, as "sudo make install" is needed.