Convert "pointer to const" to "pointer to const VLA"

In this code snippet, the large lookup table is easier to access using a pointer to the VLA :

#pragma GCC diagnostic warning "-Wcast-qual"

char
lookup(int a, int b, int c, char const *raw, int x, int y, int z)
{
    typedef char const (*DATA_PTR)[a][b][c];

    DATA_PTR data = (DATA_PTR)raw;

    return (*data)[x][y][z];
}

GCC 6.2.0 works fine when compiled with Clang 4.0.0 (trunk) , both -Wcast-qualenabled.

In function 'lookup':
warning: cast discards 'const' qualifier from pointer target type [-Wcast-qual]
   DATA_PTR data = (DATA_PTR)raw;
                   ^

The code will work as expected.

My guess is that GCC is confusing "pointer to VLA of const element" and "pointer to const VLA", but I'm getting to...

Is there a way to turn off GCC without fiddling with warnings? Is this a GCC bug?

Edit 1:

Details of the actual code:

struct table {
    int a;
    int b;
    int c;
    char *raw;
};

char
lookup2(struct table const *table, int x, int y, int z)
{
    typedef char const(*DATA_PTR)[table->a][table->b][table->c];

    DATA_PTR data;
    data = (DATA_PTR)table->raw; // GCC ok
    data = (DATA_PTR)(char const *)table->raw; // GCC raises -Wcast-qual

    return (*data)[x][y][z];
}

Edit 2:

So... the C11 draft standard says in 6.7.3/9:

If the specification of the array type includes any type qualifiers, the element type is qualified, not the array type.

See @hvd answer.

A trick of silence -Wcast-qual:

    DATA_PTR data = (DATA_PTR)(intptr_t)raw;