Resolving dependencies...
Configuring base16-bytestring-0.1.1.6...
Configuring data-default-class-0.1.2.0...
Building base16-bytestring-0.1.1.6...
Building data-default-class-0.1.2.0...
Installed base16-bytestring-0.1.1.6
Installed data-default-class-0.1.2.0
Configuring toxcore-0.2.0...
Failed to install toxcore-0.2.0
Build log ( /home/builder/.cabal/logs/ghc-8.4.3/toxcore-0.2.0-3Lg4rz9XSEe9JOLFwwZ9o9.log ):
cabal: Entering directory '/tmp/cabal-tmp-14601/toxcore-0.2.0'
Configuring toxcore-0.2.0...
cabal: Missing dependencies on foreign libraries:
* Missing (or bad) C libraries: toxcore, toxcore
This problem can usually be solved by installing the system packages that
provide these libraries (you may need the "-dev" versions). If the libraries
are already installed but in a non-standard location then you can use the
flags --extra-include-dirs= and --extra-lib-dirs= to specify where they are.If
the library files do exist, it may contain errors that are caught by the C
compiler at the preprocessing stage. In this case you can re-run configure
with the verbosity flag -v3 to see the error messages.

cabal: Leaving directory '/tmp/cabal-tmp-14601/toxcore-0.2.0'
cabal: Error: some packages failed to install:
toxcore-0.2.0-3Lg4rz9XSEe9JOLFwwZ9o9 failed during the configure step. The
exception was:
ExitFailure 1