Missing ref to mkstemps in ARM

[blankoworld]

Should fix #5264 for ARM architecture.

I recently have to compile something in ARM architecture and the compilation was broken.

Fixing this line permits to finish the compilation.

What I don't know is why this line was not added before? Is there a problem with it on ARM architecture?

How could I check that all is OK about this?

[ysbaddaden]

It was probably overlooked, since we don't have an ARM target on CI... Can you run specs related to Tempfile on the ARM target?

[blankoworld]

I tried on my Olimex, but it doesn't work. I read that it could works on a RPi?

Is there some documentation to use/compile/install Crystal on RPi (1, 2 or 3) so that I can check specs you're talking about?

At home I have RPi 1 B+, 2 and 3. So just ask me what I have to do ^_^

[opiation]

I'm guessing by Tempfile specs, @ysbaddaden is referring to a selection of specs run when using make spec verbose=1. After compiling Crystal 0.24.1 on a Pi 3 with LLVM 5.0.1 and @ysbaddaden's repo which currently ships with Crystal 0.23.1, I was able to compile and run all specs by adding the line proposed in this change. It's absence indeed appears to be an oversight.