build: add ubuntu bionic to circleci

This is done to avoid breaking the compatibility with it.

Signed-off-by: Lorenzo Fontana <fontanalorenz@gmail.com>

.circleci/config.yml

@@ -64,6 +64,37 @@ jobs:
             pushd build
             make tests
             popd
+  # Build using Ubuntu Bionic Beaver (18.04)
+  "build/ubuntu-bionic":
+    docker:
+      - image: ubuntu:bionic
+    steps:
+      - checkout
+      - run:
+          name: Update base image
+          command: apt update -y
+      - run:
+          name: Install dependencies
+          command: DEBIAN_FRONTEND=noninteractive apt install cmake build-essential clang llvm git linux-headers-generic libncurses-dev pkg-config autoconf libtool -y
+      - run:
+          name: Prepare project
+          command: |
+            mkdir build
+            pushd build
+            cmake -DBUILD_BPF=On -DUSE_BUNDLED_DEPS=On ..
+            popd
+      - run:
+          name: Build
+          command: |
+            pushd build
+            KERNELDIR=/lib/modules/$(ls /lib/modules)/build make -j4 all
+            popd
+      - run:
+          name: Run unit tests
+          command: |
+            pushd build
+            make tests
+            popd
   # Build using our own builder base image using centos 7
   # This build is static, dependencies are bundled in the falco binary
   "build/centos7":
@@ -310,6 +341,7 @@ workflows:
     jobs:
       - "build/ubuntu-focal"
       - "build/ubuntu-focal-debug"
+      - "build/ubuntu-bionic"
       - "build/centos7"
       - "build/centos7-debug"
       - "tests/integration":