prevent missing include files from making the dependency generation to fail

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@5107 a1c6a512-1295-4272-9138-f99709370657

tools/make.inc

@@ -8,12 +8,15 @@ $(OBJDIR)/%.o: %.S
 	@echo "CC $<"
 	@$(CC) $(CFLAGS) -c $< -o $@
 
+# the lame echo stuff down here is to prevent any compiler errors/warnings
+# to cause an error code to get returned and thus stop the build
 $(DEPFILE): $(SOURCES)
 	@rm -f $(DEPFILE)
 	@(for each in $(SOURCES); do \
 	  obj=`echo $$each | sed -e 's/\.c/.o/'`; \
 	  $(CC) -MM -MT "$(OBJDIR)/$$obj.o" $(CFLAGS) $$each >> $(DEPFILE) 2>/dev/null; \
-	done )
+	done; \
+	echo "oo" >/dev/null )
 
 tags:
 	@(for d in $(DIRS); do \