Fix cpptest example

[meeq]

I have verified that the cpptest example now works correctly in MAME.

Resolves #92

• Fix global constructors for C++
• Remove unused global destructors from ld script
• Minor improvements to cpptest example

According to https://gcc.gnu.org/onlinedocs/gccint/Initialization.html

Each list always begins with an ignored function pointer (which may hold 0, -1, or a count of the function pointers after it, depending on the environment).

This is followed by a series of zero or more function pointers to constructors (or destructors), followed by a function pointer containing zero.

Constructors are called in reverse order of the list

Global destructors weren't exactly hurting anything by being included, but they were never being called and there is no logical reason to call them since the system effectively halts after main returns (which it should pretty much never do).

[bryanperris]

I wondered if 0xFFFFFFFF was the result of a bug subtracting 1 from a 32-bit unsigned 0.

[rasky]

Patch looks great to me, thanks!

[anacierdem]

Let me try it on hardware and merge. Thank you! This is a really important step.

[meeq]

I'm actually noticing that the global constructor for TestClass globalClass; in the cpptest example isn't actually being called... 😞

At least it's not completely failing anymore. 😅

I'll see if I can figure out what's going on here.

[meeq]

@anacierdem I have fixed the issue with the global constructors not being called: pointers to pointers are confusing. 😅

Luckily, MAME's debugger is super awesome and let me step through to find the problem. 🎉

[anacierdem]

Those external labels make things even more complicated. I did the same many times myself too 😁 I have a minor comment. I will try to test and merge this when I have the time

[anacierdem]

Unfortunately this does not work on the real console. There is something wrong with how we arelinking it IMO b/c removing everything and only leaving a printf does not work either with that makefile. This is the barebones code I'm testing;

#include <stdio.h>
#include <libdragon.h>

static resolution_t res = RESOLUTION_320x240;
static bitdepth_t bit = DEPTH_32_BPP;

int main(void)
{
    /* enable interrupts (on the CPU) */
    init_interrupts();

    /* Initialize peripherals */
    display_init( res, bit, 2, GAMMA_NONE, ANTIALIAS_RESAMPLE );
    console_init();
    controller_init();

    console_set_render_mode(RENDER_MANUAL);
    while(1) 
    {
        console_clear();
        printf( "TEST" );
        console_render();
    }
}

Still we can merge it though as it seem to fix the ctors according to the spec.