Implement __cxa_atexit and __cxa_finalize per the Itanium spec,
and convert stdlib's atexit and exit() to to call them instead of
a custom 'C-only' atexit implementation.
Use simple stack cookies to try to provoke an assertion failure on
stack overflow.
This is far from perfect, since we use a constant cookie instead of
generating a random one on startup, but it can still help us catch
bugs, which is the primary concern right now. :^)
After some very confused debugging, I discovered that GNU make has a
main() function with this signature:
int main(int argc, char** argv, char** envp)
Apparently this is a non-standard but widely supported thing, so let's
do the same in Serenity so make works as expected.
This fixes an issue where you had to do "make PATH=..." instead of make
just picking up PATH from the environment. :^)
Now that the kernel supports thread-local storage, we can declare errno
with the __thread keyword, which causes it to be per-thread.
This should fix all the stupid issues that happen when many threads use
the same errno. :^)
