What is the precise license for this code?

[JVIon6oose]

I am in the process of writing a Gentoo ebuild. I'm assuming it is GPL 2 based on the arduino FAQ? Thanks.

[DerAndere1]

Arduino distributes arduino-preprocessor via this arduino-preprocessor github repository. When the content is downloaded directly from this github repo as a zip or cloned using git, the file headers (comments in the source code) say, I should have received a copy of the GNU General Public License along with this library. Currently, users of this repository are actually forced to "write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA" because the License text is missing. Please add a LICENSE file containing the GPL 2 license text to this repository. Also, consider the Apache 2 (or later) license as a less challenging alternative (issue https://github.com/arduino/arduino-preprocessor/issues/1)