Some versions of valgrind (such as the version on my Fedora laptop -
valgrind-3.19.0-3.fc36.x86_64) use futexes.  But futex is currently not
allowed in the seccomp filter, even with the extra calls added for
valgrind builds.  Add it, to avoid spurious valgrind failures.

Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
 Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 6f7c971..0de872e 100644
--- a/Makefile
+++ b/Makefile
@@ -115,7 +115,7 @@ qrap: $(QRAP_SRCS) passt.h
 
 valgrind: EXTRA_SYSCALLS="rt_sigprocmask rt_sigtimedwait rt_sigaction \
 			  getpid gettid kill clock_gettime mmap munmap open \
-			  unlink gettimeofday"
+			  unlink gettimeofday futex"
 valgrind: CFLAGS:=-g -O0 $(filter-out -O%,$(CFLAGS))
 valgrind: all
 
-- 
2.36.1