all: starting development of 2.8.4
test: TestCupt: added new function 'stdall'

(cherry picked from commit 4f77bc604326facd76bbb56ac7cda177851f2989)
lib: internal: pininfo: adjustUsingPinSettings: use original version for matching

This fixes matching version string pin expressions against versions with
version string id suffixes applied.

(cherry picked from commit a0a852ccdd34fa6c7c7f8292d56c3c7739807667)
lib: internal: worker: packages: getOldVersionString: return non-id-suffixed version string

(cherry picked from commit 19a7e45eb4ab5058bcbaeb4665c18d921120a806)
cmakelists: added '-pthread' to compiling and linking flags

(cherry picked from commit 34c9bf8ea4d69e69819875d367b4c16afc433d7d)
test: manage: resolver: remove: no-remove-prevents-removal-of-other-packages: added

(cherry picked from commit 75cff7dfd72c5415698941f5607316bf94cebf21)
lib: internal: nativeresolver: dependencygraph: FillHelper: getVertexPtrForEmptyPackage: refuse overriding checks

Overriding checks for user-specified relation expressions breaks the
resolver option 'no-remove' for any soft and hard user requests.

(cherry picked from commit 21f8ff428bcb4c1e5a1383b1f0fb489bb4e0c8a8)
all: 2.8.4 release
Merge branch 'fixes/2.8'
manage: resolver: upgrade: lock-step-dependency-vs-high-pinned-installed-version: added custom priority-downgrade score tests