[rcore] InitWindow() should check InitPlatform() returned value

[SuperUserNameMan]

In case PlatformInit() fails, InitWindow() should quit properly and set CORE.Window.ready = false.

Also fix rcore_template.c which returned false instead of -1, as false might be defined to 0 in raylib.h.

Note that if the user forget to check IsWindowReady() before continuing, the program might still crash in a segfault if InitPlatform() failed.

@raysan5 : could we change void InitWindow() to bool InitWindow() instead of hoping the user think about checking IsWindowReady() in case of InitPlatform() failure ?

[raysan5]

I try to avoid this kind of structure on raylib, also, not following conventions, raylib does not place spaces between parenthesis. In any case it should be:

int result = InitPlatform();
if (result == -1)  // Platform initialization failed
{
    TRACELOG(LOG_WARNING, "WINDOW: Platform initialization failed");
    //CORE.Window.ready = false;  // If platform has not been correctly initialized, this should be already "false"
    return;  // In araylib I try to avoid/minimize early returns
}

[raysan5]

Actually, afaik, there is no clear convention defined on the function return values when used for errors detection... I tried to avoid that approach for raylib but I can consider it...

[raysan5]

@SuperUserNameMan There is no clear convention on the function return values when used for errors detection... Actually, I tried to avoid that approach for most raylib functions (depite other libraries like SDL use it). I can consider it but it will require analyzing afected functions and conventions more carefully. For example, for InitWindow(), I like the void return approach for simplicity, maybe error codes could be queried a-part (like OpenGL does)... or, in case, InitWindow() returned an int what other uses it could have, other than a pure error message, i.e. for future multi-window id support.

All those questions require a review and redesign of the raylib library conventions and I prefer to consider them carefully.