Instruct Make about #include dependencies

Change-Id: I5e87f31c0a67b9cd59271f25a213aa68ee99ce51

.gitignore

@@ -2,6 +2,9 @@
 *.o
 *.elf
 
+# No dependency files
+*.d
+
 # No lex / yacc generated files.
 poincare/src/expression_lexer.cpp
 poincare/src/expression_lexer.hpp

Makefile

@@ -14,6 +14,9 @@ SFLAGS += -Ilib -I.
 # Flags - Building options
 SFLAGS += -Wall
 
+# Flags - Header dependency tracking
+SFLAGS += -MD -MP
+
 # Flags - Optimizations
 ifeq ($(DEBUG),1)
 SFLAGS += -ggdb3 -DDEBUG=1 -O0
@@ -62,6 +65,8 @@ include escher/Makefile
 include apps/Makefile
 include quiz/Makefile # Quiz should be included at the end
 
+-include $(objs:.o=.d)
+
 %.elf: $(objs)
 	@echo "LD      $@"
 	@$(LD) $^ $(LDFLAGS) -o $@