Add minimal travis support.

Add minimal travis.yml file that builds and packages falco. No actual
tests yet.

.travis.yml

@@ -0,0 +1,38 @@
+language: c
+env:
+    - BUILD_TYPE=Debug
+    - BUILD_TYPE=Release
+before_install:
+    - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+    - sudo apt-get update
+install:
+    - sudo apt-get --force-yes install g++-4.8
+    - sudo apt-get install rpm linux-headers-$(uname -r)
+    - git clone https://github.com/draios/sysdig.git ../sysdig
+before_script:
+    - export KERNELDIR=/lib/modules/$(ls /lib/modules | sort | head -1)/build
+script:
+    - set -e
+    - export CC="gcc-4.8"
+    - export CXX="g++-4.8"
+    - wget https://s3.amazonaws.com/download.draios.com/dependencies/cmake-3.3.2.tar.gz
+    - tar -xzf cmake-3.3.2.tar.gz
+    - cd cmake-3.3.2
+    - ./bootstrap --prefix=/usr
+    - make
+    - sudo make install
+    - cd ..
+    - mkdir build
+    - cd build
+    - cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+    - make VERBOSE=1
+    - make package
+#    - cd ..
+#    - test/falco_trace_regression.sh build/userspace/falco/falco
+notifications:
+  webhooks:
+    urls:
+#      - https://webhooks.gitter.im/e/fdbc2356fb0ea2f15033
+    on_success: change
+    on_failure: always
+    on_start: never

test/falco_trace_regression.sh

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+#!/bin/bash
+set -eu
+
+SCRIPT=$(readlink -f $0)
+BASEDIR=$(dirname $SCRIPT)
+
+FALCO=$1
+
+# For now, simply ensure that falco can run without errors.
+FALCO_CMDLINE="$FALCO -c $BASEDIR/../falco.yaml -r $BASEDIR/../rules/falco_rules.yaml"
+echo "Running falco: $FALCO_CMDLINE"
+$FALCO_CMDLINE > $BASEDIR/falco.log 2>&1 &
+FALCO_PID=$!
+echo "Falco started, pid $FALCO_PID"
+sleep 10
+if kill -0 $FALCO_PID > /dev/null 2>&1; then
+    echo "Falco ran successfully"
+    kill $FALCO_PID
+    ret=0
+else
+    echo "Falco did not start successfully. Full program output:"
+    cat $BASEDIR/falco.log
+    ret=1
+fi
+
+exit $ret