Add macos install, build, and test trio of scripts.

.ci/macos-build.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+
+set -e
+cd src/engine
+./build.sh ${TOOLSET}
+./b2 -v
+cd ../..

.ci/macos-test.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+
+set -e
+cd test
+./test_all.py ${TOOLSET}
+cd ..

appveyor.yml

@@ -120,5 +120,9 @@ for:
   - matrix:
       only:
         - job_build: 'XcodeBuild'
-    build_script:
+    install:
       - ./.ci/macos-install.sh
+    build_script:
+      - ./.ci/macos-build.sh
+    test_script:
+      - ./.ci/macos-test.sh