Fix Xcode C++ include path (#1844)

src/Core/Toolchains/XcodeToolchain.cs

@@ -27,16 +27,34 @@ public static string GetXcodeToolchainPath()
  return toolchainPath;
  }
 
+ public static string GetXcodeSDKPath() {
+ return Path.Combine(
+ GetXcodePath(),
+ "Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk"
+ );
+ }
+
  public static string GetXcodeCppIncludesFolder()
  {
  var toolchainPath = GetXcodeToolchainPath();
+ var sdkPath = GetXcodeSDKPath();
 
- var includePath = Path.Combine(toolchainPath, "usr/include/c++/v1");
+ var includePathSuffix = "usr/include/c++/v1";
+ var oldIncludePath = Path.Combine(toolchainPath, includePathSuffix);
+ var newIncludePath = Path.Combine(sdkPath, includePathSuffix);
 
- if (includePath == null || !Directory.Exists(includePath))
- throw new Exception($"Could not find a valid C++ include folder: {includePath}");
+ if (newIncludePath != null && Directory.Exists(newIncludePath))
+ {
+ return newIncludePath;
+ }
+
+ if (oldIncludePath != null && Directory.Exists(oldIncludePath))
+ {
+ return oldIncludePath;
+ }
 
- return includePath;
+ throw new Exception(
+ $"Could not find a valid C++ include folder in either {oldIncludePath} or {newIncludePath}");
  }
 
  public static string GetXcodeBuiltinIncludesFolder()
@@ -107,4 +125,4 @@ private static string GetXcodePathFromFileSystem()
  return toolchainPath;
  }
  }
-}
+}