Testing the WiringPi
====================
I want now to test the WiringPi I've downloaded from GitHub[1] and compiled
because of problems installing odroid-wiringpi from the ppa on armbian.
When I run 

  sudo gpio readall

I get the message:

  gpio: symbol lookup error: gpio: undefined symbol: kernelVersion

I have it under another path, so I run it using:

  sudo ~/wiringPi/gpio/gpio readall

I have prepared a breadboard with a led and a resistor, and connected
it to my Odroid N2+.

Now, to check that the wires are connected correctly, I run the script

  sudo ~/wiringPi/examples/blink.sh

I get the same message, but after I set the path in the script, it runs
correctly.

Now, I compile the example in C (blink.c).
I try to run the executable, but get the message:

  Oops: Unable to determine board revision from /proc/device-tree/system/linux,revision
  or from /proc/cpuinfo
   -> No "Hardware" line
   ->  You'd best google the error to find out why.

I can compile it with the static (suffix ".a") library instead of the shared
object (suffix ".so") as follows:

  gcc -o blink blink.c  $(pkg-config --cflags --libs libwiringpi2) -static

and then I see the led blink.
Cool! Time to by a Raspberry Pi Pico, and start a real project.

[1] Directions at 
    https://wiki.odroid.com/odroid-n2/application_note/gpio/wiringpi