glad_egl_find_core querying EGL_VERSION ahead of eglInitialize

It appears when `gladLoaderLoadEGL(NULL)` calls down to `glad_egl_find_core(NULL)`, it attempts to determine a suitable display, before then querying EGL_VERSION against it.

In the case where eglInitialize() has not previously been called (and in most scenarios, it likely would not have been), this causes Mesa to emit a debug warning (where `EGL_LOG_LEVEL=debug`) as follows:

```
libEGL debug: EGL user error 0x3001 (EGL_NOT_INITIALIZED) in eglQueryString
```

glad_egl_find_core shows:

```
static int glad_egl_find_core_{{ api|lower }}(EGLDisplay display) {
    int major, minor;
    const char *version;

    if (display == NULL) {
        display = EGL_NO_DISPLAY; /* this is usually NULL, better safe than sorry */
    }
    if (display == EGL_NO_DISPLAY) {
        display = eglGetCurrentDisplay();
    }
#ifdef EGL_VERSION_1_4
    if (display == EGL_NO_DISPLAY) {
        display = eglGetDisplay(EGL_DEFAULT_DISPLAY);
    }
#endif
#ifndef EGL_VERSION_1_5
    if (display == EGL_NO_DISPLAY) {
        return 0;
    }
#endif

    version = eglQueryString(display, EGL_VERSION);
    (void) eglGetError();

    if (version == NULL) {
        major = 1;
        minor = 0;
    } else {
        GLAD_IMPL_UTIL_SSCANF(version, "%d.%d", &major, &minor);
    }
```

Ultimately the egl_display being used here is EGL_DEFAULT_DISPLAY, and the EGL_VERSION is being returned by Mesa as 0, in which Glad then presume EGL 1.0

That seems appropriate, and I'd expect most (all?) implementations of EGL would similarly report null where eglInitialize()  has not already ocurred (perhaps not?).


I'm not sure that EGL_VERSION is intended to be queried ahead of eglInitialize() - which explains the rationale of the debug warning.

Would it be more appropriate for Glad to assume EGL version 1.0 where _display == NULL_ rather than attempting to retrieve the default display, and subsequently query GL_VERSION against it ?

I accept that there are very probably good reasons for the current behaviour, and this issue is really just splitting hairs (it is inconsequential, and easily ignored)

Also, thank you for creating and maintaining this fantastic (and very useful) library. 

Reference: https://gitlab.freedesktop.org/mesa/mesa/-/issues/10710

