The Compact C Type Format in the GNU toolchain

I can only guess how this became the default.

I'd guess that debuginfo, in a world where debuggers are a special thing that is explicitly run by human beings when things go wrong, is something huge that is only *needed* when things go wrong, when there will be a human around who can install the necessary big packages. But you never want to compile something without any debug info for use in a production environment because if things go wrong you then have no debuginfo to use to diagnose it! So -g -O2 has become a sort of de facto standard for CFLAGS.

Of course the "you only need it when things go wrong" attitude has now been retarding the development of always-on systemwide debugging tools for something like fifteen years; but nobody wants to add extensive debuginfo shrinking machinery because it will slow down the link for something that is only rarely needed. It seems to me that the only *reason* debuginfo is only rarely needed is that tools that use debuginfo routinely cannot be developed because it can never be relied on to be present, because it is too big... it's a vicious circle.