Doesn't work on macOS with big files

[VolodymyrBS]

Compiler fails to compile the file with error.

error CS1504: Source file '***/Assets/TrueSync/Physics/Farseer/Common/PhysicsLogic/RealExplosion.cs' could not be opened -- GetCPInfoExW

To Reproduce
Steps to reproduce the behavior:

1. Clone repo https://github.com/VolodymyrBS/CSharpCompilerSettingsForUnityBugRepro.git
2. Import project on macOS
3. Check Console
4. See an error

Environment:

• Version 1.0.1
• Platform: Editor Mac
• Unity version: [e.g. 2019.3.5f1]
• Build options: any
• Injected compiler version - 3.5.0, 3.7.0

Additional context
Probably it's related to this issue
mono/mono#12603
ILSpy shows that System.Text.Encoding.CodePages.dll library inside Microsoft.Net.Compiler package use WinApi

Note: Can't share the original project but only part of it enough to reproduce the error.
Note: Error will also occure if you try to directly call mono <path to downloaded csc.exe> <path to RealExplosion.cs>

[mob-sakai]

@VolodymyrBS
Thank you for reporting.
The issue was reproduced in my environment.

Using Unity's built-in mono, the build was failed.

$ /Applications/Unity/Hub/Editor/2019.3.2f1/Unity.app/Contents/MonoBleedingEdge/bin/mono --version
Mono JIT compiler version 5.11.0 ((HEAD/4fbd4767c98 Mon Dec 16 02:55:50 GMT 2019)
...

$ /Applications/Unity/Hub/Editor/2019.3.2f1/Unity.app/Contents/MonoBleedingEdge/bin/mono -noconfig @rsp_test
Microsoft (R) Visual C# Compiler version 3.5.0-beta4-20153-05 (20b9af91)
Copyright (C) Microsoft Corporation. All rights reserved.

error CS1504: Source file '/Users/takashi.sakai/repos/CSharpCompilerSettingsForUnityBugRepro/Assets/TrueSync/Physics/Farseer/Common/PhysicsLogic/RealExplosion.cs' could not be opened -- GetCPInfoExW

Using the new version of mono, the build was successful.

$ mono --version
Mono JIT compiler version 6.12.0.90 (2020-02/d3daacdaa80 Thu Jul 30 16:18:06 EDT 2020)
...

$ mono -noconfig @rsp_test
Microsoft (R) Visual C# Compiler version 3.5.0-beta4-20153-05 (20b9af91)
Copyright (C) Microsoft Corporation. All rights reserved.

Assets/TrueSync/Unity/TSTransform2D.cs(87,22): warning CS0649: Field 'TSTransform2D._serialized' is never assigned to, and will always have its default value false

Response file: test_rsp

[mob-sakai]

Plans:

• Add `Use System Mono' option

  • Pros: Simple.
  • Cons: All developers have to install mono on their machines.

• Use self-contained csc

  • Pros: Mono is not needed to run csc.
  • Cons: Increasing the download size of csc
  • Cons: csc package needs to be rebuilt.

[mob-sakai]

Fixed in 1.1.0