dai_effect_value() returns value of the single effect, not cumulative value of
the object being evaluated.

See patch #4974


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25763 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Made 1.5.2 the minimum libtool version.

See patch #5002


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25764 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Do not omit help about base's "NoAggressive" flag when happyborders is disabled.

See bug #22405


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25765 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Introduce fc_at_quick_exit() as wrapper around at_quick_exit() if it exist.
Use it to register callback to shutdown spawned server on the client side
even in case of quick_exit().

See patch #4998


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@25768 a0f10bec-cc02-0410-94fc-a9cfff90b4cd