ci: use Ninja on macOS

azure-pipelines.yml

@@ -69,6 +69,7 @@ jobs:
         TMPDIR: $(Agent.TempDirectory)
         PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
         LEAK_CHECK: leaks
+        CMAKE_OPTIONS: -G Ninja
 
 - job: windows_vs_amd64
   displayName: 'Windows (Visual Studio; amd64)'

ci/setup-osx.sh

@@ -3,6 +3,6 @@
 set -x
 
 brew update
-brew install pkgconfig zlib curl openssl libssh2
+brew install pkgconfig zlib curl openssl libssh2 ninja
 
 ln -s /Applications/Xcode.app/Contents/Developer/usr/lib/libLeaksAtExit.dylib /usr/local/lib