package/screen: bump version to 4.7.0

package/screen: bump version to 4.7.0

Release notes:
https://lists.gnu.org/archive/html/info-gnu/2019-10/msg00000.html

Removed patches applied upstream:

- 0001-compiler-sanity-checks.patch
https://git.savannah.gnu.org/cgit/screen.git/commit/?h=v.4.7.0&id=6b320186db7df1e58fdd2c836af54c86cc596981

- 0003-cross-compilation-AC_TRY_RUN.patch
https://git.savannah.gnu.org/cgit/screen.git/commit/?h=v.4.7.0&id=abba47ce4206506c49858d944e904fff86ae65cc

- 0004-cross-compilation-ignore-host-fs.patch
https://git.savannah.gnu.org/cgit/screen.git/commit/?h=v.4.7.0&id=c573b89139e7a068f5573abd565605bed60f293f

- 0005-avoid-identifying-as-SVR4.patch
https://git.savannah.gnu.org/cgit/screen.git/commit/?h=v.4.7.0&id=ec90292592dd2c9d5c108390841e3df24e377ed5

Rebased 0001-no-memcpy-fallback.patch

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>