CPP: Model 'alloca'.

cpp/ql/src/semmle/code/cpp/models/implementations/Allocation.qll

@@ -77,6 +77,9 @@ class MallocAllocationFunction extends AllocationFunction {
         or
         // CoTaskMemAlloc(size)
         name = "CoTaskMemAlloc" and sizeArg = 0
+        or
+        // alloca(size)
+        name = "alloca" and sizeArg = 0
       )
     )
   }