I downloaded the source on the 15th of February. However, when I try to compile the game, I get an error. The following seems to be the relevant part of the terminal output.
obj/game.o: In function `game::setup()':
/home/jukka/Downloads/Cataclysm-DDA-master/game.cpp:203: undefined reference to `game::opening_screen()'
collect2: ld returned 1 exit status
make: *** [cataclysm] Error 1
The full make output is in spoilers because it is rather long.
~/Downloads/Cataclysm-DDA-master $ make
g++ -g -MMD -c action.cpp -o obj/action.o
g++ -g -MMD -c artifact.cpp -o obj/artifact.o
g++ -g -MMD -c bionics.cpp -o obj/bionics.o
g++ -g -MMD -c bodypart.cpp -o obj/bodypart.o
g++ -g -MMD -c calendar.cpp -o obj/calendar.o
g++ -g -MMD -c catacurse.cpp -o obj/catacurse.o
g++ -g -MMD -c color.cpp -o obj/color.o
g++ -g -MMD -c computer.cpp -o obj/computer.o
g++ -g -MMD -c construction.cpp -o obj/construction.o
g++ -g -MMD -c crafting.cpp -o obj/crafting.o
g++ -g -MMD -c debug.cpp -o obj/debug.o
g++ -g -MMD -c defense.cpp -o obj/defense.o
g++ -g -MMD -c disease.cpp -o obj/disease.o
g++ -g -MMD -c event.cpp -o obj/event.o
g++ -g -MMD -c faction.cpp -o obj/faction.o
g++ -g -MMD -c field.cpp -o obj/field.o
g++ -g -MMD -c game.cpp -o obj/game.o
g++ -g -MMD -c gamemode.cpp -o obj/gamemode.o
g++ -g -MMD -c graffiti.cpp -o obj/graffiti.o
g++ -g -MMD -c help.cpp -o obj/help.o
g++ -g -MMD -c input.cpp -o obj/input.o
g++ -g -MMD -c inventory.cpp -o obj/inventory.o
g++ -g -MMD -c inventory_ui.cpp -o obj/inventory_ui.o
g++ -g -MMD -c item.cpp -o obj/item.o
g++ -g -MMD -c itypedef.cpp -o obj/itypedef.o
g++ -g -MMD -c iuse.cpp -o obj/iuse.o
g++ -g -MMD -c keypress.cpp -o obj/keypress.o
g++ -g -MMD -c lightmap.cpp -o obj/lightmap.o
g++ -g -MMD -c line.cpp -o obj/line.o
g++ -g -MMD -c main.cpp -o obj/main.o
g++ -g -MMD -c mapbuffer.cpp -o obj/mapbuffer.o
g++ -g -MMD -c map.cpp -o obj/map.o
g++ -g -MMD -c mapdata.cpp -o obj/mapdata.o
g++ -g -MMD -c mapgen.cpp -o obj/mapgen.o
g++ -g -MMD -c mapitemsdef.cpp -o obj/mapitemsdef.o
g++ -g -MMD -c melee.cpp -o obj/melee.o
g++ -g -MMD -c mission.cpp -o obj/mission.o
g++ -g -MMD -c missiondef.cpp -o obj/missiondef.o
g++ -g -MMD -c mission_end.cpp -o obj/mission_end.o
g++ -g -MMD -c mission_fail.cpp -o obj/mission_fail.o
g++ -g -MMD -c mission_place.cpp -o obj/mission_place.o
g++ -g -MMD -c mission_start.cpp -o obj/mission_start.o
g++ -g -MMD -c monattack.cpp -o obj/monattack.o
g++ -g -MMD -c mondeath.cpp -o obj/mondeath.o
g++ -g -MMD -c mongroupdef.cpp -o obj/mongroupdef.o
g++ -g -MMD -c monitemsdef.cpp -o obj/monitemsdef.o
g++ -g -MMD -c monmove.cpp -o obj/monmove.o
g++ -g -MMD -c monster.cpp -o obj/monster.o
g++ -g -MMD -c mtypedef.cpp -o obj/mtypedef.o
g++ -g -MMD -c mutation.cpp -o obj/mutation.o
g++ -g -MMD -c mutation_data.cpp -o obj/mutation_data.o
g++ -g -MMD -c name.cpp -o obj/name.o
g++ -g -MMD -c newcharacter.cpp -o obj/newcharacter.o
g++ -g -MMD -c npc.cpp -o obj/npc.o
g++ -g -MMD -c npcmove.cpp -o obj/npcmove.o
g++ -g -MMD -c npctalk.cpp -o obj/npctalk.o
g++ -g -MMD -c options.cpp -o obj/options.o
g++ -g -MMD -c output.cpp -o obj/output.o
g++ -g -MMD -c overmap.cpp -o obj/overmap.o
g++ -g -MMD -c player.cpp -o obj/player.o
g++ -g -MMD -c posix_time.cpp -o obj/posix_time.o
g++ -g -MMD -c ranged.cpp -o obj/ranged.o
g++ -g -MMD -c rng.cpp -o obj/rng.o
g++ -g -MMD -c settlement.cpp -o obj/settlement.o
g++ -g -MMD -c setvector.cpp -o obj/setvector.o
g++ -g -MMD -c skill.cpp -o obj/skill.o
g++ -g -MMD -c texthash.cpp -o obj/texthash.o
g++ -g -MMD -c tileray.cpp -o obj/tileray.o
g++ -g -MMD -c trapdef.cpp -o obj/trapdef.o
g++ -g -MMD -c trapfunc.cpp -o obj/trapfunc.o
g++ -g -MMD -c tutorial.cpp -o obj/tutorial.o
g++ -g -MMD -c vehicle.cpp -o obj/vehicle.o
g++ -g -MMD -c veh_interact.cpp -o obj/veh_interact.o
g++ -g -MMD -c veh_typedef.cpp -o obj/veh_typedef.o
g++ -g -MMD -c weather.cpp -o obj/weather.o
g++ -g -MMD -c wish.cpp -o obj/wish.o
g++ -o cataclysm -g -MMD \
obj/action.o obj/artifact.o obj/bionics.o obj/bodypart.o obj/calendar.o obj/catacurse.o obj/color.o obj/computer.o obj/construction.o obj/crafting.o obj/debug.o obj/defense.o obj/disease.o obj/event.o obj/faction.o obj/field.o obj/game.o obj/gamemode.o obj/graffiti.o obj/help.o obj/input.o obj/inventory.o obj/inventory_ui.o obj/item.o obj/itypedef.o obj/iuse.o obj/keypress.o obj/lightmap.o obj/line.o obj/main.o obj/mapbuffer.o obj/map.o obj/mapdata.o obj/mapgen.o obj/mapitemsdef.o obj/melee.o obj/mission.o obj/missiondef.o obj/mission_end.o obj/mission_fail.o obj/mission_place.o obj/mission_start.o obj/monattack.o obj/mondeath.o obj/mongroupdef.o obj/monitemsdef.o obj/monmove.o obj/monster.o obj/mtypedef.o obj/mutation.o obj/mutation_data.o obj/name.o obj/newcharacter.o obj/npc.o obj/npcmove.o obj/npctalk.o obj/options.o obj/output.o obj/overmap.o obj/player.o obj/posix_time.o obj/ranged.o obj/rng.o obj/settlement.o obj/setvector.o obj/skill.o obj/texthash.o obj/tileray.o obj/trapdef.o obj/trapfunc.o obj/tutorial.o obj/vehicle.o obj/veh_interact.o obj/veh_typedef.o obj/weather.o obj/wish.o -lncurses
obj/game.o: In function `game::setup()':
/home/jukka/Downloads/Cataclysm-DDA-master/game.cpp:203: undefined reference to `game::opening_screen()'
collect2: ld returned 1 exit status
make: *** [cataclysm] Error 1
Please advice how I can fix it.
edit: Nevermind, I cloned the code with Git and it compiled fine.