Building poke fails on link stage.

[Konstantinos Chasialis]

Hello,

I am having troubles building poke on my mac (m1 processor) after the latest 
patch where new changes to pk-mi-json.c/.h were introduced.

More specifically, I am facing the following issue :

Undefined symbols for architecture arm64:
  "_rpl_vsnprintf", referenced from:
      _jerror in poke-pk-mi-json.o
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I would like to point out that when I comment out the use of vsnprintf poke 
builds successfully.

Also, when I use vsnprintf function on a custom .c file (i.e. test.c on 
Desktop) it compiles successfully w/o the use of any external libraries.

Jose pointed out that I should add vsnprintf module to gnulib_modules, which I 
did.

Unfortunately, I still get the same error.

Any ideas?

Thanks in advance,
Kostas.