[mutter/wip/carlosg/coverity-fixes: 4/13] cogl: Fix broken check for COGL_DISABLE_GL_EXTENSION envvar

[Carlos Garnacho <carlosg src gnome org>]

commit 3f74c6e43aa2e048657c751faee5ed27139f132d
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sun Oct 24 20:54:17 2021 +0200

    cogl: Fix broken check for COGL_DISABLE_GL_EXTENSION envvar
    
    This check was always true since the variable is already set in the
    if() condition above. Presumably this was meant to check for empty
    strings, so do that.
    
    CID: #1491518

 cogl/cogl/driver/gl/cogl-util-gl.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)
---
diff --git a/cogl/cogl/driver/gl/cogl-util-gl.c b/cogl/cogl/driver/gl/cogl-util-gl.c
index 80c4179130..59d2e74d44 100644
--- a/cogl/cogl/driver/gl/cogl-util-gl.c
+++ b/cogl/cogl/driver/gl/cogl-util-gl.c
@@ -363,13 +363,17 @@ _cogl_context_get_gl_extensions (CoglContext *context)
       char **split_env_disabled_extensions;
       char **src, **dst;
 
-      if (env_disabled_extensions)
-        split_env_disabled_extensions =
-          g_strsplit (env_disabled_extensions,
-                      ",",
-                      0 /* no max tokens */);
+      if (*env_disabled_extensions)
+        {
+          split_env_disabled_extensions =
+            g_strsplit (env_disabled_extensions,
+                        ",",
+                        0 /* no max tokens */);
+        }
       else
-        split_env_disabled_extensions = NULL;
+        {
+          split_env_disabled_extensions = NULL;
+        }
 
       for (dst = ret, src = ret;
            *src;