only hook into WinForms on Windows for Mac compatibility (#126)

src/StardewModdingAPI/Program.cs

@@ -5,7 +5,9 @@ using System.IO;
 using System.Linq;
 using System.Reflection;
 using System.Threading;
+#if SMAPI_FOR_WINDOWS
 using System.Windows.Forms;
+#endif
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 using StardewModdingAPI.Events;
@@ -208,8 +210,10 @@ namespace StardewModdingAPI
 
         public static void RunGame()
         {
+#if SMAPI_FOR_WINDOWS
             Application.ThreadException += Log.Application_ThreadException;
             Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
+#endif
             AppDomain.CurrentDomain.UnhandledException += Log.CurrentDomain_UnhandledException;
 
             try

src/StardewModdingAPI/StardewModdingAPI.csproj

@@ -92,6 +92,9 @@
   </PropertyGroup>
   <Choose>
     <When Condition="$(OS) == 'Windows_NT'">
+      <PropertyGroup>
+        <DefineConstants>$(DefineConstants);SMAPI_FOR_WINDOWS</DefineConstants>
+      </PropertyGroup>
       <ItemGroup>
         <Reference Include="Microsoft.Xna.Framework, Version=4.0.0.0, Culture=neutral, PublicKeyToken=842cf8be1de50553, processorArchitecture=x86">
           <Private>False</Private>
@@ -117,6 +120,9 @@
       </ItemGroup>
     </When>
     <Otherwise>
+      <PropertyGroup>
+        <DefineConstants>$(DefineConstants);SMAPI_FOR_UNIX</DefineConstants>
+      </PropertyGroup>
       <ItemGroup>
         <Reference Include="MonoGame.Framework">
           <HintPath>$(GamePath)\MonoGame.Framework.dll</HintPath>
@@ -142,7 +148,7 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Drawing" />
-    <Reference Include="System.Windows.Forms" />
+    <Reference Include="System.Windows.Forms" Condition="$(OS) == 'Windows_NT'" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />