Silence compiler warnings [-Wdiscarded-qualifiers]

Silence compiler warnings [-Wdiscarded-qualifiers]

It's just a quirk that free takes non-const: it doesn't actually modify
the value pointed to, either conceptually or in practice, it merely looks
up the memory block using the pointer and deallocates it.

Unfortunately, the compiler will emit  warning when attempting to free()
a "const char *". So either switch to a pointer to non-const or cast to
(void *) when calling free() on a pointer to const.

Signed-off-by: Dimitri Papadopoulos <3350651-DimitriPapadopoulos@users.noreply.gitlab.com>