Otdfbt

I am trying to install Liquidity on a VM with Ubuntu 18.04.2 LTS following this instruction http://www.liquidity-lang.org/doc/installation/index.html . Everything goes well until stage 4: Install Liquidity dependencies: make build-deps. After entering this command, I get the error message:

opam install . --deps-only
[WARNING] Running as root is not recommended
[WARNING] Failed checks on liquidity package definition from source at
 git+file:///root/liquidity#next:
 error 57: Synopsis and description must not be both empty
The following actions will be performed:
 ∗ install conf-libcurl 1
 ∗ install conf-libsodium 1
 ∗ install ocurl 0.8.2
 ∗ install sodium 0.6.0
===== ∗ 4 =====
Do you want to continue? [Y/n] y

<><> Gathering sources ><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
[ocurl.0.8.2] found in cache
[sodium.0.6.0] found in cache

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
[ERROR] The compilation of conf-libcurl failed at
 "/root/.opam/opam-init/hooks/sandbox.sh build pkg-config libcurl".
[ERROR] The compilation of conf-libsodium failed at
 "/root/.opam/opam-init/hooks/sandbox.sh build pkg-config libsodium".

#=== ERROR while compiling conf-libsodium.1 ===================================#
# context 2.0.4 | linux/x86_64 | ocaml-base-compiler.4.06.1 | https://opam.ocaml.org/#c7c0bde9
# path ~/.opam/liquidity/.opam-switch/build/conf-libsodium.1
# command ~/.opam/opam-init/hooks/sandbox.sh build pkg-config libsodium
# exit-code 1
# env-file ~/.opam/log/conf-libsodium-1310-d2d111.env
# output-file ~/.opam/log/conf-libsodium-1310-d2d111.out


#=== ERROR while compiling conf-libcurl.1 =====================================#
# context 2.0.4 | linux/x86_64 | ocaml-base-compiler.4.06.1 | https://opam.ocaml.org/#c7c0bde9
# path ~/.opam/liquidity/.opam-switch/build/conf-libcurl.1
# command ~/.opam/opam-init/hooks/sandbox.sh build pkg-config libcurl
# exit-code 1
# env-file ~/.opam/log/conf-libcurl-1310-c61e7b.env
# output-file ~/.opam/log/conf-libcurl-1310-c61e7b.out



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build conf-libcurl 1
│ λ build conf-libsodium 1
└─ 
╶─ No changes have been performed

The packages you requested declare the following system dependencies. Please
make sure they are installed before retrying:
 libcurl4-gnutls-dev libsodium-dev

Makefile:61: recipe for target 'build-deps' failed
make: *** [build-deps] Error 31
root@ubuntu-s-2vcpu-2gb-fra1-01:~/liquidity#

I'm not a very experienced Linux user. What am I doing wrong? Please, help

Actually, error 57: Synopsis and description must not be both empty should be seen as a warning emitted by opam. The reason of the failure is given at the end. It's due to absence of some system dependencies. Try to install them as follows before recompiling Liquidity:

sudo apt-get install libcurl4-gnutls-dev libsodium-dev