anv: Check if memfd_create is already defined.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103909
Signed-off-by: Vinson Lee <vlee@freedesktop.org>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
diff --git a/meson.build b/meson.build
index e2ba3cb..4a2e817 100644
--- a/meson.build
+++ b/meson.build
@@ -617,7 +617,7 @@
   endif
 endforeach
 
-foreach f : ['strtof', 'mkostemp', 'posix_memalign', 'timespec_get']
+foreach f : ['strtof', 'mkostemp', 'posix_memalign', 'timespec_get', 'memfd_create']
   if cc.has_function(f)
     pre_args += '-DHAVE_@0@'.format(f.to_upper())
   endif