w64: Use uintptr_t in exec.c

w64: Use uintptr_t in exec.c

Replace all type casts to 'long' or 'unsigned long' by 'intptr_t' or 'uintptr_t'.

For type casts which are only used to extract the lower bits of an address
or to modify those bits, signedness does not matter. There I always use 'uintptr_t'.

Signed-off-by: Stefan Weil <sw@weilnetz.de>