From 4ea3ab78849820e4b32b573baf6bb3f8743c20dd Mon Sep 17 00:00:00 2001
From: Matthijs Kooijman <matthijs@stdin.nl>
Date: Wed, 20 Feb 2013 17:30:44 +0100
Subject: [PATCH] Enable dependency tracking for libraries and core

This makes sure a library or core file gets rebuild when a header file
it depends on is changed, preventing weird surprises when the
application is recompiled with the new header values but the library
isn't.

For most users, this won't be strictly needed, but anyone working on a
library or even the Arduino core, this is must to prevent surprises or
needing a make clean between every build attempt.
---
 arduino-mk/Arduino.mk | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/arduino-mk/Arduino.mk b/arduino-mk/Arduino.mk
index 01a3df1..148e6b6 100644
--- a/arduino-mk/Arduino.mk
+++ b/arduino-mk/Arduino.mk
@@ -623,9 +623,6 @@ LOCAL_OBJ_FILES = $(LOCAL_C_SRCS:.c=.o)   $(LOCAL_CPP_SRCS:.cpp=.o) \
 		$(LOCAL_INO_SRCS:.ino=.o) $(LOCAL_AS_SRCS:.S=.o)
 LOCAL_OBJS      = $(patsubst %,$(OBJDIR)/%,$(LOCAL_OBJ_FILES))
 
-# Dependency files
-DEPS            = $(LOCAL_OBJS:.o=.d)
-
 ifneq ($(words $(LOCAL_PDE_SRCS) $(LOCAL_INO_SRCS)), 1)
     $(error Need exactly one .pde or .ino file)
 endif
@@ -751,6 +748,9 @@ LIB_OBJS      = $(patsubst $(ARDUINO_LIB_PATH)/%.c,$(OBJDIR)/libs/%.o,$(LIB_C_SR
 USER_LIB_OBJS = $(patsubst $(USER_LIB_PATH)/%.cpp,$(OBJDIR)/libs/%.o,$(USER_LIB_CPP_SRCS)) \
 		$(patsubst $(USER_LIB_PATH)/%.c,$(OBJDIR)/libs/%.o,$(USER_LIB_C_SRCS))
 
+# Dependency files
+DEPS            = $(LOCAL_OBJS:.o=.d) $(LIB_OBJS:.o=.d) $(USER_LIB_OBJS:.o=.d) $(CORE_OBJS:.o=.d)
+
 # Using += instead of =, so that CPPFLAGS can be set per sketch level
 CPPFLAGS      += -mmcu=$(MCU) -DF_CPU=$(F_CPU) -DARDUINO=$(ARDUINO_VERSION) \
 			-I. -I$(ARDUINO_CORE_PATH) -I$(ARDUINO_VAR_PATH)/$(VARIANT) \
@@ -806,16 +806,16 @@ $(call show_separator)
 
 # library sources
 $(OBJDIR)/libs/%.o: $(ARDUINO_LIB_PATH)/%.c | $(OBJDIR)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
+	$(CC) -MMD -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 $(OBJDIR)/libs/%.o: $(ARDUINO_LIB_PATH)/%.cpp | $(OBJDIR)
-	$(CC) -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
+	$(CC) -MMD -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
 
 $(OBJDIR)/libs/%.o: $(USER_LIB_PATH)/%.cpp | $(OBJDIR)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
+	$(CC) -MMD -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 $(OBJDIR)/libs/%.o: $(USER_LIB_PATH)/%.c | $(OBJDIR)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
+	$(CC) -MMD -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 # normal local sources
 COMMON_DEPS := Makefile
@@ -851,10 +851,10 @@ $(OBJDIR)/%.s: $(OBJDIR)/%.cpp $(COMMON_DEPS) | $(OBJDIR)
 
 # core files
 $(OBJDIR)/%.o: $(ARDUINO_CORE_PATH)/%.c $(COMMON_DEPS) | $(OBJDIR)
-	$(CC) -c $(CPPFLAGS) $(CFLAGS) $< -o $@
+	$(CC) -MMD -c $(CPPFLAGS) $(CFLAGS) $< -o $@
 
 $(OBJDIR)/%.o: $(ARDUINO_CORE_PATH)/%.cpp $(COMMON_DEPS) | $(OBJDIR)
-	$(CXX) -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
+	$(CXX) -MMD -c $(CPPFLAGS) $(CXXFLAGS) $< -o $@
 
 # various object conversions
 $(OBJDIR)/%.hex: $(OBJDIR)/%.elf $(COMMON_DEPS)