gnu: libtiff: Update to 4.0.7.
* gnu/packages/image.scm (libtiff): Update to 4.0.7.
[source]: Update URL and remove obsolete patches.
[home-page]: Update URL.
[native-inputs]: Add gcc-5.
(libtiff-4.0.7): Delete variable.
* gnu/packages/patches/libtiff-CVE-2015-8665+CVE-2015-8683.patch,
gnu/packages/patches/libtiff-CVE-2016-3623.patch,
gnu/packages/patches/libtiff-CVE-2016-3945.patch,
gnu/packages/patches/libtiff-CVE-2016-3990.patch,
gnu/packages/patches/libtiff-CVE-2016-3991.patch,
gnu/packages/patches/libtiff-CVE-2016-5314.patch,
gnu/packages/patches/libtiff-CVE-2016-5321.patch,
gnu/packages/patches/libtiff-CVE-2016-5323.patch,
gnu/packages/patches/libtiff-oob-accesses-in-decode.patch,
gnu/packages/patches/libtiff-oob-write-in-nextdecode.patch: Delete files.
* gnu/local.mk (dist_patch_DATA): Remove them.