define KNOWN_PLATFORMS

+--------------------------------------------------------+
| PLATFORM      | DESCRIPTION                            |
+--------------------------------------------------------+
| PM3RDV4 (def) | Proxmark3 rdv4      with AT91SAM7S512  |
+--------------------------------------------------------+
| PM3EVO        | Proxmark3 EVO       with AT91SAM7S512  |
+--------------------------------------------------------+
| PM3EASY       | Proxmark3 rdv3 Easy with AT91SAM7S256  |
+--------------------------------------------------------+
| PM3RDV2       | Proxmark3 rdv2      with AT91SAM7S512  |
+--------------------------------------------------------+
| PM3OLD256     | Proxmark3 V1        with AT91SAM7S256  |
+--------------------------------------------------------+
| PM3OLD512     | Proxmark3 V1        with AT91SAM7S512  |
+--------------------------------------------------------+

Options to define platform:
(1) Run make with PLATFORM specified as follows:
make PLATFORM=PM3EASY

(2) Save a file called Makefile.platform with contents:
PLATFORM=PM3EASY

endef

PLTNAME = Unknown Platform

ifeq ($(PLATFORM),PM3RDV4)
  MCU = AT91SAM7S512
  PLATFORM_DEFS = -DWITH_SMARTCARD -DWITH_FLASH
  PLTNAME = Proxmark3 rdv4
else ifeq ($(PLATFORM),PM3EVO)
  MCU = AT91SAM7S512
  PLTNAME = Proxmark3 EVO
else ifeq ($(PLATFORM),PM3EASY)
  MCU = AT91SAM7S256
  PLTNAME = Proxmark3 rdv3 Easy
else ifeq ($(PLATFORM),PM3RDV2)
  MCU = AT91SAM7S512
  PLTNAME = Proxmark3 rdv2
else ifeq ($(PLATFORM),PM3OLD256)
  MCU = AT91SAM7S256
  PLTNAME = Proxmark3 V1 with AT91SAM7S256
else ifeq ($(PLATFORM),PM3OLD512)
  MCU = AT91SAM7S512
  PLTNAME = Proxmark3 V1 with AT91SAM7S512
else
  $(error Invalid or empty PLATFORM: $(PLATFORM). Known platforms: $(KNOWN_PLATFORMS))
endif

export PLATFORM
export PLTNAME
export MCU
export PLATFORM_DEFS