Automatically find build number from CI environment

build/targets/KoreBuild.DefaultBuildSettings.props

@@ -1,4 +1,13 @@
 <Project>
+  <!-- Use build number from CI if available -->
+  <PropertyGroup Condition=" '$(BuildNumber)' == '' ">
+    <!--
+      See https://confluence.jetbrains.com/display/TCD10/Predefined+Build+Parameters.
+      This environment variable is automatically set by TeamCity.
+    -->
+    <BuildNumber Condition=" '$(BUILD_NUMBER)' != '' ">$(BUILD_NUMBER)</BuildNumber>
+  </PropertyGroup>
+
   <!-- Create a temporary build number if not assigned by the CI server -->
   <PropertyGroup Condition=" '$(BuildNumber)' == '' ">
     <!--