Use external handlers in tizenrt-artik05x target

[glistening]

This patch includes followings:

• Use external handlers in jerry-ext.
• Make jerry_main similar to other ports. (including options)
• Merge jerry_port.c into jerry_main.c
  jerry_port is clearly out of jerry-core.

This patch not included following:

• Use jerry-libm, instead of system libm.
  It is already included.
  We choose to use jerry-libm since the result of cube-3d sunspider was inaccurate
  when using NuttX libm.
• Correct setjmp/longjmp implementation.
  I tried to bring the source from NuttX port.
  Unfortunately it does not work in tizenrt-artik05x as it is.
  I will take a closer look the code and make sure it works.

JerryScript-DCO-1.0-Signed-off-by: Sanggyu Lee sg5.lee@samsung.com

[glistening]

Here is my next plan. I will port setjmp/longjmp on artik05x (cortex-r4). This architecture seems not support some instructions, which were used in setjmp/longjmp on stm32f4 (cortex-m4). After landing this, I would like to close #1774. Then, I will make next step for porting promise on tizenrt-artik05x.

[zherczeg]

LGTM

[yichoi]

LGTM

[robertsipka]

Just a question about the setjmp/longjmp implementation that may be a different from the source of the NuttX port. Is the hard-float mode enabled? The stm32f4 NuttX port's setjmp implementation expects that the hard-float mode is used and stores s16-s31 vfp registers to buffer, pointed with r0 register, and increases the register on size of stored data.

[robertsipka]

Sorry, I've just seen the #1823 issue, but the question is still valid, and it concerns both of the vstm and vldm instructions.