feat: Makefile and test program

Makefile

@@ -0,0 +1,48 @@
+# ---------------------------------------------------------------------------- #
+#                                   VARIABLES                                  #
+# ---------------------------------------------------------------------------- #
+
+NAME_BASE     := libft_malloc
+HOSTTYPE      ?= $(shell uname -m)_$(shell uname -s)
+NAME          := $(NAME_BASE)_$(HOSTTYPE).so
+SYMLINK       := $(NAME_BASE).so
+
+CC            := cc
+CFLAGS        := -Wall -Wextra -Werror -fPIC
+LDFLAGS       := -shared
+
+SRC_DIR       := src
+INC_DIR       := inc
+OBJ_DIR       := obj
+
+SRCS          := $(wildcard $(SRC_DIR)/*.c)
+OBJS          := $(patsubst $(SRC_DIR)/%.c,$(OBJ_DIR)/%.o,$(SRCS))
+
+INCLUDES      := -I$(INC_DIR)
+
+# ---------------------------------------------------------------------------- #
+#                                    RULES                                     #
+# ---------------------------------------------------------------------------- #
+
+all: $(NAME) symlink
+
+$(OBJ_DIR)/%.o: $(SRC_DIR)/%.c
+	@mkdir -p $(OBJ_DIR)
+	$(CC) $(CFLAGS) $(INCLUDES) -c $< -o $@
+
+$(NAME): $(OBJS)
+	$(CC) $(LDFLAGS) -o $@ $^
+
+symlink: $(NAME)
+	@ln -sf $(NAME) $(SYMLINK)
+
+clean:
+	@rm -rf $(OBJ_DIR)
+
+fclean: clean
+	@rm -f $(NAME) $(SYMLINK)
+
+re: fclean all
+
+.PHONY: all clean fclean re symlink
+

inc/malloc.h

@@ -0,0 +1,11 @@
+#ifndef MALLOC_H
+# define MALLOC_H
+
+#include <stdlib.h>
+#include <unistd.h>
+
+#define PROUT "42\n"
+
+void *malloc(size_t size);
+
+#endif

main.c

@@ -0,0 +1,6 @@
+#include <stdlib.h>
+
+int main(void) {
+	malloc(42);
+	return 0;
+}

src/malloc.c

@@ -0,0 +1,7 @@
+#include "malloc.h"
+
+void * malloc(size_t size) {
+	(void)size;
+	write(1, PROUT, 3);
+	return 0;
+}

test.sh

@@ -0,0 +1,4 @@
+#!/bin/sh
+make
+gcc main.c -o test_malloc.out
+LD_PRELOAD=./libft_malloc.so ./test_malloc.out