Add Kokoro presubmit scripts

kokoro/macos/presubmit.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+set -e # Fail on any error.
+set -x # Display commands being run.
+
+BUILD_ROOT=$PWD
+
+cd github/cppdap
+
+git submodule update --init
+
+if [ "$BUILD_SYSTEM" == "cmake" ]; then
+    mkdir build
+    cd build
+
+    cmake .. -DCPPDAP_BUILD_EXAMPLES=1 -DCPPDAP_BUILD_TESTS=1 -DCPPDAP_WARNINGS_AS_ERRORS=1
+    make -j$(sysctl -n hw.logicalcpu)
+
+    ./cppdap-unittests
+else
+    echo "Unknown build system: $BUILD_SYSTEM"
+    exit 1
+fi