This commits updates the contrib sources to version 8.7.1.
This version requires more random entropy as it queries OpenSSL
about the current random state and will bail if it is not sufficient.
Doubling the content of the '<inline>' VFS plugin as used in static
configurations seems satisfactory.
Furthermore DNS resolving needs a configured '<pipe>' plugin to work
properly.
Fixes#5184.
The original size of 16K impedes the batched processing of network
packets. Changing the value to 256K reduces the number of context
switches when downloading large files and thereby improves the
throughput by more than 25% (base-hw on qemu_x86_64, using fetchurl
to download a file of 100 MiB via the NIC router from lighttpd).
Issue #4697