These days, GCC has at least minimal documentation for its VLAIS extension.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@255723 91177308-0d34-0410-b5e6-96231b3b80d8

www/comparison.html

@@ -55,8 +55,8 @@
     by Clang. For instance, in C mode, GCC supports
     <a href="http://gcc.gnu.org/onlinedocs/gcc/Nested-Functions.html">nested
     functions</a> and has an
-    <a href="http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37428">undocumented
-    extension allowing VLAs in structs</a>.
+    <a href="https://gcc.gnu.org/onlinedocs/gcc/Variable-Length.html">extension
+    allowing VLAs in structs</a>.
     </ul>
 
     <p>Pro's of clang vs GCC:</p>