travis: run build checks and complete build

This will allow various issues before actually running the tests in our
CI. Use `-j 2` since Travis CI usually runs on 2 cores and some parts of
the build benefit from that.

Updates #11730

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>

.travis/build.sh

@@ -4,6 +4,7 @@ set -o errexit
 
 export CFLAGS="-Werror"
 
+make -j 2
 make unit-tests
 
 $HOME/gopath/bin/goveralls -coverprofile=coverage-all.out -service=travis-ci || true

.travis/prepare.sh

@@ -48,3 +48,4 @@ export PATH="/usr/local/clang/bin:$PATH"
 # disable go modules to avoid downloading all dependencies when doing go get
 GO111MODULE=off go get golang.org/x/tools/cmd/cover
 GO111MODULE=off go get github.com/mattn/goveralls
+GO111MODULE=off go get github.com/gordonklaus/ineffassign