Error while loading shared libraries: liblua.so - makefile

Question

I'm trying to launch a client for a school project that has an AI developed in Lua, I have added liblua.so in a /lib/ folder at the root of my program's folder.
After compiling and launching said program, I get the following error:
./zappy_ai: error while loading shared libraries: liblua.so: cannot open shared object file: No such file or directory
From what I understand I must do something at the compilation for my program to know where my shared library is located.
Here's the relevant part of my Makefile:
CXX = g++
BASE_FLAGS = -Wall -Wextra -Iincludes
AI_NAME = zappy_ai
AI_PATH = ./sources/client/
AI_FLAGS = $(BASE_FLAGS) \
-L./lib/ \
-I./includes/client/ \
-I./include/ \
-std=c++11 \
AI_LDFLAGS = -llua
AI_SRCS = main.cpp \
Client.cpp \
Params/Params.cpp \
Params/Option.cpp \
SocketTCP.cpp \
Misc/Error.cpp
AI_OBJS = $(addprefix $(AI_PATH), $(AI_SRCS:.cpp=.cpp.o))
%.cpp.o : %.cpp
#printf "%b[Compilation]%b %-50s" $(BLUE) $(RESET) $<
#$(CXX) $(FLAGS) -c $< -o $#
#printf "%bOK%b\n" $(GREEN) $(RESET)
$(AI_NAME) : FLAGS = $(AI_FLAGS)
$(AI_NAME) : $(AI_OBJS)
#$(CXX) $^ -o $# $(AI_LDFLAGS)
#printf "%b[Message]%b AI compilation done\n\n" $(YELLOW) $(RESET)
What should I add in order to be able to launch my program and have it find my shared library?

Answer 1

tldr:
$ LD_LIBRARY_PATH="$LD_LIBRARY_PATH:./lib" ./zappy_ai
Longer explanation:
You've dynamically linked
zappy_ai
against
./lib/liblua.so
by using
LDFLAGS = -L./lib/
and
LDLIBS = -llua
The resulting zappy_ai executable requires that same ./lib/ to be present within the LD_LIBRARY_PATH environment variable when the dynamic linker/loader attempts to resolve the -llua symbols that zappy_ai uses.