v260
mountfsd: add call for creating a foreign UID owned dir in dir owned by caller
various: check meson feature flag early
tree-wide: Migrate to pidref_safe_fork()
tree-wide: Introduce sd-forward.h and shared-forward.h headers
tree-wide: Remove unnecessary SIGCHLD blocking
xstatx_full(): add flag to acquire STATX_MNT_ID_UNIQUE if we can, with fallback.