add flex lexer

Makefile

@@ -1,3 +1,19 @@
-build:
+LEXER_SRC = src/lexer/lex.l
+LEXER_C = src/lexer/lex.yy.c
+LEXER_H = src/lexer/lex.yy.h
+
+CFILES = $(shell find src -name '*.c')
+BINARY = bin/cargon
+
+all: $(BINARY)
+
+$(LEXER_C) $(LEXER_H): $(LEXER_SRC)
+	flex --header-file=$(LEXER_H) -o $(LEXER_C) $(LEXER_SRC)
+
+$(BINARY): $(CFILES) $(LEXER_C) $(LEXER_H)
 	mkdir -p bin
-	gcc -O3 -o bin/cargon $(shell find src -name '*.c') -lm -Wall -Wextra -Werror
+	gcc -O3 -o $(BINARY) $(CFILES) -lm -Wall -Wextra -Wno-unused-function
+
+clean:
+	rm -rf bin
+	rm -f $(LEXER_C) $(LEXER_H)