Disable zink fallback in EGL

In mesa 23.3.x zink broke on nvidia, crashing in eglCreateContext.
In the same release, zink was added as a fallback between the
hardware drivers and swrast.
Any application that was previously falling back to swrast
now instead crashes, when using the nvidia vulkan driver.

How exactly do you reach zink or previously swrast when using
nvidia you may ask?
One common path may be EGL applications using EGL_EXT_platform_xcb.
The nvidia driver does not support it, thus GLVND tries the next
driver which is mesa, mesa doesn't find any suitable hardware driver
and thus falls back to zink or swrast.

Until zink is stable again on nvidia, we should disable the zink
fallback to prevent applications crashing instead of falling back
to swrast.

There should be no need to also disable the GLX fallback to zink
as i'm not aware of a call path that would lead to using mesa when
the nvidia drivers are installed.

RHBZ 2255599
RHBZ 2255768
MESA 10340
MESA 10341

disable-zink-egl-fallback.patch

@@ -0,0 +1,26 @@
+diff --git a/src/egl/main/eglapi.c b/src/egl/main/eglapi.c
+index d50be23e871..e3697622635 100644
+--- a/src/egl/main/eglapi.c
++++ b/src/egl/main/eglapi.c
+@@ -695,17 +695,21 @@ eglInitialize(EGLDisplay dpy, EGLint *major, EGLint *minor)
+          if (disp->Options.ForceSoftware)
+             RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
+          else {
++#if 0
+             bool success = false;
+             if (!disp->Options.Zink && !getenv("GALLIUM_DRIVER")) {
+                disp->Options.Zink = EGL_TRUE;
+                success = _eglDriver.Initialize(disp);
+             }
+             if (!success) {
++#endif
+                disp->Options.Zink = EGL_FALSE;
+                disp->Options.ForceSoftware = EGL_TRUE;
+                if (!_eglDriver.Initialize(disp))
+                   RETURN_EGL_ERROR(disp, EGL_NOT_INITIALIZED, EGL_FALSE);
++#if 0
+             }
++#endif
+          }
+       }
+ 

mesa.spec

@@ -76,6 +76,7 @@ Source1:        Mesa-MLAA-License-Clarification-Email.txt
 Patch10:        gnome-shell-glthread-disable.patch
 Patch11:        0001-intel-compiler-reemit-boolean-resolve-for-inverted-i.patch
 Patch12:        0001-intel-compiler-fix-release-build-unused-variable.patch
+Patch13:        disable-zink-egl-fallback.patch
 
 BuildRequires:  meson >= 1.2.0
 BuildRequires:  gcc