I converted my Unity 4.5.1f3 game project to iOS and opened the same in XCode 5.1.1.
To resolve the issues with Mach-O linker error I kept the Library and Framework search paths blank in build settings as I have done successfully in other XCode projects.
This removed the Mach-O linker error. However the above error Lexical or Preprocessor issue 'Unity/GlesHelper.h' file not found
error in Xcode 5.1.1 from Unity is reported now.
I have tried the following build settings:
- setting Always search user paths to Yes
- adding an entry to the Header search path:
$(SRCROOT)/Classes/Unity
I am not using any plugin other than NGUI 2.7 for Unity.
The screenshot of XCode with the error reported in the editor sub window is available at the link http://forum.unity3d.com/threads/lexical-or-preprocessor-issue-unity-gleshelper-h-file-not-found-error-in-xcode-5-1-1-from-unity.267386/
Kindly share your feedback on resolving this issue expediently. Please let me know if you need any more specific data to address this issue.