add make.mk and rules.mk to help new makefile example

examples/make.mk

@@ -0,0 +1,65 @@
+#
+# Common make definition for all examples
+#
+
+# Compiler 
+CROSS_COMPILE = arm-none-eabi-
+CC = $(CROSS_COMPILE)gcc
+CXX = $(CROSS_COMPILE)g++
+OBJCOPY = $(CROSS_COMPILE)objcopy
+SIZE = $(CROSS_COMPILE)size
+MKDIR = mkdir
+SED = sed
+CP = cp
+RM = rm
+
+# Select the board to build for.
+ifeq ($(BOARD),)
+  $(info You must provide a BOARD parameter with 'BOARD=')
+  $(info Possible values are:)
+  $(info $(sort $(subst /.,,$(subst $(TOP)/hw/bsp/,,$(wildcard $(TOP)/hw/bsp/*/.)))))
+  $(error BOARD not defined)
+else
+  ifeq ($(wildcard $(TOP)/hw/bsp/$(BOARD)/.),)
+    $(error Invalid BOARD specified)
+  endif
+endif
+
+# Build directory
+BUILD = build-$(BOARD)
+
+# Board specific
+include $(TOP)/hw/bsp/$(BOARD)/board.mk
+
+# Compiler Flags
+CFLAGS += \
+	-fsingle-precision-constant \
+	-fno-strict-aliasing \
+	-Wdouble-promotion \
+	-Wno-endif-labels \
+	-Wstrict-prototypes \
+	-Wall \
+	-Werror \
+	-Werror-implicit-function-declaration \
+	-Wfloat-equal \
+	-Wundef \
+	-Wshadow \
+	-Wwrite-strings \
+	-Wsign-compare \
+	-Wmissing-format-attribute \
+	-Wno-deprecated-declarations \
+	-Wnested-externs \
+	-Wunreachable-code \
+	-Wno-error=lto-type-mismatch \
+	-ffunction-sections \
+	-fdata-sections
+
+# This causes lots of warning with nrf5x build due to nrfx code
+# CFLAGS += -Wcast-align
+
+# Debugging/Optimization
+ifeq ($(DEBUG), 1)
+  CFLAGS += -O0 -ggdb
+else
+  CFLAGS += -flto -Os
+endif