Taken from libei, with slight modifications. The general approach is:
basic data types use _autofoo_ to call the maching foo function on
cleanup. Struct types use _unref_, _destory_, _free_, whichever applies
to that struct.
Notably: attribute syntax depends on where it's declared [1] so in the
following examles only a, b, and d have the autofree attribute:
_autofree_ char *a, *b;
char *c, _autofree *d;
Simplest way to ensure it's all correct to keep the declarations one per
line.
[1] https://gcc.gnu.org/onlinedocs/gcc/Attribute-Syntax.html#Attribute-Syntax
Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1184>
