What's the proper lib variable for a makefile? - makefile

Question

Running into trouble with libraries in makefiles again. Every time I try to get back into C make gives me a pain with libs.
make -pf /dev/null says the correct vars should be LDLIBS and LOADLIBES but the following doesn't alter the run command at all:
LOADLIBES=testing
LDFLAGS=testing
LDLIBS=testing
Needless to say this gives me errors because the -L flags don't end up in the command. Anyone know what's going on?
Full makefile below (Derivitave of Z Shaw's makefile)
OPTLIBS=$(xml2-config --libs)
OPTFLAGS=$(xml2-config --cflags)
STD=c99
CFLAGS=-std=$(STD) -g -O2 -Wall -Wextra -Isrc -rdynamic -DNDEBUG $(OPTFLAGS)
LDLIBS=-ldl $(OPTLIBS)
PREFIX?=/usr/local
SOURCES=$(wildcard src/**/*.c src/*.c)
OBJECTS=$(patsubst %.c,%.o,$(SOURCES))
TEST_SRC=$(wildcard tests/*_tests.c)
TESTS=$(patsubst %.c,%,$(TEST_SRC))
TARGET=build/lib.a
SO_TARGET=$(patsubst %.a,%.so,$(TARGET))
# The Target Build
all: cls $(TARGET) $(SO_TARGET) tests
dev: CFLAGS=-std=$(STD) -g -Wall -Isrc -Wall -Wextra $(OPTFLAGS)
dev: all
$(TARGET): CFLAGS += -fPIC
$(TARGET): build $(OBJECTS)
ar rcs $# $(OBJECTS)
ranlib $#
$(SO_TARGET): $(TARGET) $(OBJECTS)
$(CC) -shared -o $# $(OBJECTS)
build:
#mkdir -p build
#mkdir -p bin
# The Unit Tests
$(TESTS): $(TARGET)
.PHONY: tests
tests: LDLIBS += $(TARGET)
tests: $(TESTS)
sh ./tests/runtests.sh
valgrind:
VALGRIND="valgrind --log-file=/tmp/valgrind-%p.log" $(MAKE)
# The Cleaner
clean: cls
rm -rf build $(OBJECTS) $(TESTS)
rm -f tests/tests.log
find . -name "*.gc*" -exec rm {} \;
rm -rf `find . -name "*.dSYM" -print`
# The Install
install: all
install -d $(DESTDIR)/$(PREFIX)/lib/
install $(TARGET) $(DESTDIR)/$(PREFIX)/lib/
# The Checker
BADFUNCS='[^_.>a-zA-Z0-9](str(n?cpy|n?cat|xfrm|n?dup|str|pbrk|tok|_)|stpn?cpy|a?sn?printf|byte_)'
check:
#echo Files with potentially dangerous functions.
#egrep $(BADFUNCS) $(SOURCES) || true
# Clear screen for unspammy terminals
cls:
ifdef TERM
clear
endif

Answer 1

You aren't using LDFLAGS, etc in your link command. Make that something along the lines of:
$(SO_TARGET): $(TARGET) $(OBJECTS)
$(CC) -shared $(LDFLAGS) -o $# $(OBJECTS) $(LDLIBS)

Answer 2

It tells the linker to link the dl library, which is located at /usr/lib/libdl.so. -l is the switch to add a library, dl is the name of it (without the lib prefix or .so extension).
This library includes functions for dynamically loading shared libraries.