Merge pull request #1356 from haukepetersen/fix_sam3x_newlibnano

cpu - sam3x8e: added switch for newlib-nano specs

boards/arduino-due/Makefile.include

@@ -1,4 +1,3 @@
-
 # define the cpu used by the arduino due board
 export CPU = sam3x8e
 
@@ -30,19 +29,18 @@ export PORT
 # define build specific options
 export CPU_USAGE = -mcpu=cortex-m3
 export CFLAGS += -ggdb -g3 -std=gnu99 -Os -Wall -Wstrict-prototypes $(CPU_USAGE) -mlittle-endian -mthumb -mthumb-interwork -nostartfiles
-export CFLAGS += -DREENTRANT_SYSCALLS_PROVIDED
+export CFLAGS += -flto -ffunction-sections -fdata-sections -fno-builtin
 export ASFLAGS += -ggdb -g3 -mcpu=cortex-m4 $(FPU_USAGE) -mlittle-endian
 export LINKFLAGS += -g3 -ggdb -std=gnu99 $(CPU_USAGE) $(FPU_USAGE) -mlittle-endian -static -lgcc -mthumb -mthumb-interwork -nostartfiles
 # linkerscript specified in cpu/Makefile.include
 export LINKFLAGS += -T$(LINKERSCRIPT)
 export OFLAGS += -O binary
 export FFLAGS += -e -w -v -b bin/$(BOARD)/$(APPLICATION).hex
 
-# additional compiler and linker flags to enable newlib-nano and optimize for it
-# CAREFUL: newlib-nano is not supported by the ubuntu arm-none-eabi- toolchain, so its disabled by default
-#export CFLAGS += -flto -ffunction-sections -fdata-sections -fno-builtin
-#export LINKFLAGS += -specs=nano.specs -lc -lnosys
-
+# use the nano-specs of the NewLib when available
+ifeq ($(shell $(LINK) -specs=nano.specs -E - 2>/dev/null >/dev/null </dev/null ; echo $$?),0)
+export LINKFLAGS += -specs=nano.specs -lc -lnosys
+endif
 
 # export board specific includes to the global includes-listing
 export INCLUDES += -I$(RIOTBOARD)/$(BOARD)/include