Enable build on Debian Jessie
* Makefile.am (EXTRA_DIST): Add new patches. * patches/gnutls-2.12.23/25_updatedgdocfrommaster.patch, patches/scute-1.4.0/workaround-broken-libtool.patch, patches/w32pth-2.0.5/workaround-broken-libtool.patch: New.
The gnutls patch fixes building of doc. Taken from debian.
The two other patches workaround the libtool problem.