[CI] Test meson builds

Currently this only tests meson builddir, it still does nothing with
what meson outputs. But we know that makefile's days are numbered.

.ci/lib/stage-build-nosgx.jenkinsfile

@@ -4,4 +4,17 @@ stage('build') {
         make ${MAKEOPTS} test
         make ${MAKEOPTS} -C Pal/src PAL_HOST=Skeleton
     '''
+
+    try {
+        sh '''
+            meson build \
+                -Ddirect=enabled \
+                -Dsgx=disabled
+            ninja -C build
+            DESTDIR=$PWD/install ninja -C build install
+        '''
+    } finally {
+        archiveArtifacts 'build/meson-logs/**/*'
+    }
+    sh 'rm -rf build install'
 }

.ci/lib/stage-build-sgx.jenkinsfile

@@ -32,4 +32,17 @@ stage('build') {
             make ${MAKEOPTS} -C Pal/src/host/Linux-SGX/sgx-driver
         make ${MAKEOPTS}
     '''
+
+    try {
+        sh '''
+            meson setup build \
+                -Ddirect=disabled \
+                -Dsgx=enabled
+            ninja -C build
+            DESTDIR=$PWD/install ninja -C build install
+        '''
+    } finally {
+        archiveArtifacts 'build/meson-logs/**/*'
+    }
+    sh 'rm -rf build install'
 }

.ci/ubuntu16.04.dockerfile

@@ -35,6 +35,7 @@ RUN apt-get update \
        libxxf86vm1 \
        linux-headers-4.4.0-161-generic \
        net-tools \
+       ninja-build \
        pkg-config \
        protobuf-c-compiler \
        python \
@@ -52,7 +53,7 @@ RUN apt-get update \
        wget \
        zlib1g \
        zlib1g-dev \
-    && /usr/bin/pip3 install protobuf \
+    && /usr/bin/pip3 install protobuf meson==0.45.1 \
 
 # Add the user UID:1001, GID:1001, home at /leeroy
     && groupadd -r leeroy -g 1001 \

.ci/ubuntu18.04.dockerfile

@@ -34,6 +34,7 @@ RUN apt-get update && env DEBIAN_FRONTEND=noninteractive apt-get install -y \
     libxrender1 \
     libxxf86vm1 \
     linux-headers-4.15.0-20-generic \
+    meson \
     net-tools \
     pkg-config \
     protobuf-c-compiler \

.gitignore

@@ -1,4 +1,5 @@
 /build
+/install
 
 # No editor backup files.
 *.sw*