Unity - Scripting API:

public function SetBuildPropertyForConfig(configGuid: string, name: string, value: string): void;

public function SetBuildPropertyForConfig(configGuids: string[], name: string, value: string): void;

Parameters

configGuid	The GUID of the build configuration as returned by BuildConfigByName().
configGuids	An array of GUIDs of build configurations.
name	The name of the build property.
value	The value of the build property.

Sets the build property to the given value in the given build property.