small fixes
- allow for forward slash in windows
- vsnprintf using NULL instead of "". see https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf , chapter 7.21.6.5 "If n is zero, nothing is written, and s may be a null pointer"
- remove unused, non-posix sys/random.h
Edited by Henri Manson