winpr is now always build as single library.
The build option MONOLITHIC_BUILD doesn't influence this behavior anymore.
The only exception is winpr-makecert-tool which is still build as extra
library.
This obsoletes complex_libraries for winpr.
This adds a ringbuffer implementation that targets bytes sending.
The ringbuffer can grow when there's not enough room, that's why it's
not thread-safe (locking must be done externally). It will be shrinked
to its initial size as soon as the used bytes are the half of the
initial size.