Fix Archim 2 build for PIO

Marlin/Makefile

@@ -686,7 +686,7 @@ ifeq ($(HARDWARE_VARIANT), Teensy)
 
 else ifeq ($(HARDWARE_VARIANT), archim)
   CDEFS      += -DARDUINO_SAM_ARCHIM -DARDUINO_ARCH_SAM -D__SAM3X8E__ -DUSB_VID=0x27b1 -DUSB_PID=0x0001 -DUSBCON '-DUSB_MANUFACTURER="UltiMachine"' '-DUSB_PRODUCT="Archim"'
-  LIB_CXXSRC += variant.cpp IPAddress.cpp Reset.cpp RingBuffer.cpp Stream.cpp UARTClass.cpp  USARTClass.cpp abi.cpp new.cpp watchdog.cpp CDC.cpp PluggableUSB.cpp  USBCore.cpp
+  LIB_CXXSRC += variant.cpp IPAddress.cpp Reset.cpp RingBuffer.cpp Stream.cpp UARTClass.cpp  USARTClass.cpp abi.cpp new.cpp watchdog.cpp CDC.cpp PluggableUSB.cpp USBCore.cpp
   LIB_SRC    += cortex_handlers.c iar_calls_sam3.c syscalls_sam3.c dtostrf.c itoa.c
 
   ifeq ($(U8GLIB), 1)

Marlin/src/pins/pins.h

@@ -454,7 +454,7 @@
 #elif MB(ARCHIM1)
   #include "sam/pins_ARCHIM1.h"                 // SAM3X8E                                env:DUE env:DUE_debug
 #elif MB(ARCHIM2)
-  #include "sam/pins_ARCHIM2.h"                 // SAM3X8E                                env:DUE env:DUE_debug
+  #include "sam/pins_ARCHIM2.h"                 // SAM3X8E                                env:DUE_archim env:DUE_archim_debug
 #elif MB(ALLIGATOR)
   #include "sam/pins_ALLIGATOR_R2.h"            // SAM3X8E                                env:DUE env:DUE_debug
 #elif MB(ADSK)

platformio.ini

@@ -207,6 +207,25 @@ build_flags   = ${common.build_flags}
   -mpoke-function-name
 
 #
+# Archim SAM
+#
+[env:DUE_archim]
+platform      = atmelsam
+board         = due
+src_filter    = ${common.default_src_filter} +<src/HAL/DUE>
+build_flags   = ${common.build_flags}
+  -DARDUINO_SAM_ARCHIM -DARDUINO_ARCH_SAM -D__SAM3X8E__ -DUSBCON
+
+[env:DUE_archim_debug]
+# Used when WATCHDOG_RESET_MANUAL is enabled
+platform      = atmelsam
+board         = due
+src_filter    = ${common.default_src_filter} +<src/HAL/DUE>
+build_flags   = ${common.build_flags}
+  -DARDUINO_SAM_ARCHIM -DARDUINO_ARCH_SAM -D__SAM3X8E__ -DUSBCON
+  -funwind-tables -mpoke-function-name
+
+#
 # NXP LPC176x ARM Cortex-M3
 #
 [env:LPC1768]