make check fails on OS X due to make build-libc

[gz-c]

This fails on OS X, the solution is to do brew install snaipe/soft/criterion

• The README should be updated to include this instruction for OS X machines wishing to build libskycoin
• libskycoin should not be built by default in make check. Travis should perform the libskycoin test separately

mkdir -p build/usr/tmp build/usr/lib build/usr/include
mkdir -p build/libskycoin bin include
rm -Rf build/libskycoin/*
go build -buildmode=c-shared  -o build/libskycoin/libskycoin.so ./lib/cgo/main.go
go build -buildmode=c-archive -o build/libskycoin/libskycoin.a  ./lib/cgo/main.go
mv build/libskycoin/libskycoin.h include/
cp lib/cgo/tests/*.c build/libskycoin/
gcc -o bin/test_libskycoin_shared build/libskycoin/*.c -lskycoin                    -lcriterion -Iinclude -Ibuild/usr/include -L build/libskycoin -Lbuild/usr/lib
build/libskycoin/check_cipher.c:2:10: fatal error: 'criterion/criterion.h' file not found
#include <criterion/criterion.h>
         ^~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
make: *** [test-libc] Error 1

[gz-c]

Upon further review,

make install-deps-libc should be documented in the "Client Libraries" section https://github.com/skycoin/skycoin#client-libraries of the README.

This section also says:

Skycoin implements client libraries which export core functionality for usage from other programming languages. Read the corresponding README file for further details.

This corresponding README file should be linked to.

make install-deps-libc should detect OS X and use brew install snaipe/soft/criterion

[gz-c]

#1029 removes make test-libc from the list of targets for make test. Travis will still run these tests.

[olemis]

@gz-c dependencies to run make test-libc are installed by the make install-deps-libc target . The later is not executed by the former because Criterion may be installed globally .

I did not use brew install version for MacOS X before because I had some issues with that approach .

Should I use Debian / Ubuntu packages on Linux ?

[gz-c]

Since make test-libc is separated, it is sufficient to document installation instructions in the README, either installing from source via the make command or using the system's package manager