Allow CONFIG_BOARD_SIZE_LIMIT to be specified in hex

Use the printf command to convert the number in any valid format into
the expected decimal format.  The resulting errors should be printed to
stderr.
Signed-off-by: NJoe Hershberger <joe.hershberger@ni.com>

Makefile

@@ -390,12 +390,12 @@ __LIBS := $(subst $(obj),,$(LIBS)) $(subst $(obj),,$(LIBBOARD))
 ifneq ($(CONFIG_BOARD_SIZE_LIMIT),)
 BOARD_SIZE_CHECK = \
 	@actual=`wc -c $@ | awk '{print $$1}'`; \
-	limit=$(CONFIG_BOARD_SIZE_LIMIT); \
+	limit=`printf "%d" $(CONFIG_BOARD_SIZE_LIMIT)`; \
 	if test $$actual -gt $$limit; then \
-		echo "$@ exceeds file size limit:"; \
-		echo "  limit:  $$limit bytes"; \
-		echo "  actual: $$actual bytes"; \
-		echo "  excess: $$((actual - limit)) bytes"; \
+		echo "$@ exceeds file size limit:" >&2 ; \
+		echo "  limit:  $$limit bytes" >&2 ; \
+		echo "  actual: $$actual bytes" >&2 ; \
+		echo "  excess: $$((actual - limit)) bytes" >&2; \
 		exit 1; \
 	fi
 else