Restrict Pdb2XmlCommand to DEBUG mode on Windows only (#3641)

Author: lextm

ILSpy/Commands/Pdb2XmlCommand.cs

@@ -16,7 +16,7 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-#if DEBUG
+#if DEBUG && WINDOWS
 
 using System.Collections.Generic;
 using System.Composition;