arc4random_buf() is a pretty standard libc function on Unix'oid platforms,
but not all our targets have it, thus we need a fallback there. Currently we
have GenerateRandomData(), which either just wraps arc4random_buf() or provides
some fallback implementation.
For those cases it's easier to just implement missing functions directly
instead of having custom wrapper functions. So, drop GenerateRandomData()
in favor of arc4random_buf() and provide fallback implementation for where
it is missing.
Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
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