trinity: fix build with glibc 2.27

trinity: fix build with glibc 2.27

glibc 2.27 added a system call wrapper for memfd_create() which collides
with the local definition of the same symbol in trinity. Add a patch to
detect the presence of memfd_create(), and avoid collision.

Fixes:
http://autobuild.buildroot.net/results/fda/fda07327395921fdc79cbb4f24b662209fee1be1/
http://autobuild.buildroot.net/results/f98/f98f43657cbf519a626257af5a21c8c228423856/
http://autobuild.buildroot.net/results/575/57558c418ea5c5011ac22e5236beff4d823c825b/

Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>