updated

featureful_makefile/Makefile

@@ -1,3 +1,33 @@
+
+#Setting a default configuration if invoked with just "make":
+CFG ?= debug
+
+# Config specific settings
+ifeq ($(CFG),debug)
+CFLAGS += -DDEBUG
+else
+CFLAGS += -O3 -DNDEBUG
+endif
+
+inform:
+ifneq ($(CFG),release)
+ifneq ($(CFG),debug)
+	@echo "Invalid configuration "$(CFG)" specified."
+	@echo
+	@echo "Possible choices for configuration are 'CFG=release' and 'CFG=debug'"
+	@exit 1
+endif
+endif
+	@echo "Configuration "$(CFG)
+	@echo "--------------------------------------------------"
+
+rule : dep | inform
+
+BUILD_DIR = build/$(CFG)
+OBJS_DIR = $(BUILD_DIR)/objs
+#--------------------------------------------------
+
+
 BINARY=bin
 CODEDIRS=. lib
 INCDIRS=. ./include/ # can be list