zephyr: Revamp jerry-port.c, add more functions. (#1411)

The file was named jerry-entry.c and not even built. Rename for clarity,
and add jerry_port_fatal(), jerry_port_get_current_time(),
jerry_port_get_time_zone() functions. User-visible result is that
if Date builtin is enabled (e.g. if building "full" config, its
Date.now() method can be used to measure relative time difference,
e.g. for benchmarking).

JerryScript-DCO-1.0-Signed-off-by: Paul Sokolovsky paul.sokolovsky@linaro.org

targets/zephyr/src/Makefile

@@ -19,4 +19,4 @@ endif
 # Adding path for jerry script APIs
 ZEPHYRINCLUDE += -I$(JERRY_INCLUDE)
 
-obj-y += main-zephyr.o getline-zephyr.o
+obj-y += main-zephyr.o getline-zephyr.o jerry-port.o