build: compile with -g and add .h files as dependencies

Makefile

 CC = gcc
-CFLAGS = -O2 -Wall -Wextra -std=c99
+CFLAGS = -g -O2 -Wall -Wextra -std=c99
 
 TOOLS = bin2fex fex2bin
 
@@ -10,6 +10,9 @@ all: $(TOOLS)
 clean:
 	@rm -vf $(TOOLS)
 
+$(TOOLS): sunxi-tools.h
+bin2fex: bin2fex.h
+
 .gitignore: Makefile
 	@for x in $(TOOLS) '*.o' '*.swp'; do \
 		echo $$x; \