buildscript {
    ext {
        kotlin_version = '1.1.2-2'
        osgi_platform = 'win32.win32.x86_64'
        swt_version = '3.105.3'
    }
//...
}

configurations.all {
    resolutionStrategy {
        dependencySubstitution {
            // The maven property ${osgi.platform} is not handled by Gradle
            // so we replace the dependency, using the osgi platform from the project settings
            substitute module('org.eclipse.platform:org.eclipse.swt.${osgi.platform}') with module("org.eclipse.platform:org.eclipse.swt.$osgi_platform:$swt_version")
        }
    }
}