cast: fix cast of void * when we don't have GCC features.
[ccan] / ccan / cast / test /
drwxr-xr-x   ..
-rw-r--r-- 475 compile_fail-cast_const.c
-rw-r--r-- 479 compile_fail-cast_const2.c
-rw-r--r-- 482 compile_fail-cast_const3.c
-rw-r--r-- 376 compile_fail-cast_signed-const.c
-rw-r--r-- 487 compile_fail-cast_signed-sizesame.c
-rw-r--r-- 206 compile_fail-cast_signed.c
-rw-r--r-- 301 compile_fail-cast_static-2.c
-rw-r--r-- 295 compile_fail-cast_static-3.c
-rw-r--r-- 182 compile_fail-cast_static.c
-rw-r--r-- 167 compile_ok-cast_void.c