CC = gcc
FILES = workfile.c insert.c
TARGETS = exe
CFLAGS = -o
DBUG =
RM = rm -f
OBJS = *.o

#Master Rule

all: $(TARGETS)

#Build

exe: workfile.o insert.o
    $(CC) $(CFLAGS) $(DBUG) workfile.o insert.o exe

#workfile

workfile.o: workfile.c
    $(CC) $(DBUG) -c *.c

insert.o: insert.c
    $(CC) $(DBUG) -c *.c

clean:
    $(RM) $(TARGETS) $(OBJS)

$make all
gcc  -c *.c
gcc -o  workfile.o insert.o exe
gcc: error: exe: No such file or directory
make: *** [exe] Error 1

exe: workfile.o insert.o
    $(CC) $(CFLAGS) $(DBUG) workfile.o insert.o exe

exe: workfile.o insert.o
    $(CC) $(CFLAGS) $(DBUG) -o exe workfile.o insert.o

CC = gcc
FILES = workfile.c insert.c
TARGETS = exe
CFLAGS =
DBUG =
RM = rm -f
OBJS = *.o

#Master Rule

all: $(TARGETS)

#Build

exe: workfile.o insert.o
    $(CC) $(CFLAGS) $(DBUG) -o exe workfile.o insert.o

#workfile

workfile.o: workfile.c
    $(CC) $(DBUG) -o workfile.o -c workfile.c

insert.o: insert.c
    $(CC) $(DBUG) -o insert.o -c insert.c

clean:
    $(RM) $(TARGETS) $(OBJS)

CFLAGS = -Wall -Wextra -Werror

exe: workfile.o insert.o
    $(CC) $(CFLAGS) $(DBUG) workfile.o insert.o -o exe

CFLAGS =
OUTFILE = fancy_exe
[...]
$(CC) $(CFLAGS) $(DBUG) workfile.o insert.o -o $(OUTFILE)