[devops] Enable verbose build. (#15366)

* [devops] Enable verbose build.

* Allow to set the build in verbose when the pipeline is in debug mode.

Co-authored-by: Manuel de la Pena <mandel@microsoft.com>

tools/devops/automation/templates/build/build.yml

@@ -246,8 +246,14 @@ steps:
     set -e
     echo "##vso[task.setvariable variable=TESTS_BOT;isOutput=true]$AGENT_NAME"
     time make -C $(Build.SourcesDirectory)/xamarin-macios/ reset
-    time make -C $(Build.SourcesDirectory)/xamarin-macios/ all -j8
-    time make -C $(Build.SourcesDirectory)/xamarin-macios/ install -j8
+    MAKE_FLAGS=""
+
+    if [[ "$SYSTEM_DEBUG" == "true" ]]; then
+      MAKE_FLAGS="V=1 -w"
+    fi
+
+    time make -C $(Build.SourcesDirectory)/xamarin-macios/ all -j8 $MAKE_FLAGS
+    time make -C $(Build.SourcesDirectory)/xamarin-macios/ install -j8 $MAKE_FLAGS
   name: build
   displayName: 'Build'
   timeoutInMinutes: 300