Which only appears relevant if you disregard critical differences like this:
The GCC garbage collector GGC is only invoked explicitly. In contrast with many other garbage collectors, it is not implicitly invoked by allocation routines when a lot of memory has been consumed. [1]
[1] https://gcc.gnu.org/onlinedocs/gccint/Invoking-the-garbage-c...
https://gcc.gnu.org/onlinedocs/gccint/Type-Information.html