qemu: fix build with glibc 2.27

qemu: fix build with glibc 2.27

glibc version 2.27 added a wrapper for the memfd_create system call. The
wrapper prototype collides with a static declaration of memfd_create.
Add upstream patch to correctly detect the glibc provided memfd_create
definition.

Fixes:
http://autobuild.buildroot.net/results/b82/b825c0cd397424b1fc7fa87c580e1757dc25c588/
http://autobuild.buildroot.net/results/9aa/9aa3853d23c0dc72bf3632b4d66ae39f597f5250/
http://autobuild.buildroot.net/results/b13/b13039ba602b9d500b939d259816a39ba24e1ba2/

Cc: Francois Perrad <francois.perrad@gadz.org>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Romain Naour <romain.naour@gmail.com>
Tested-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>