Fix possible deadlocks

4 jobs for master in 9 minutes and 18 seconds (queued for 1 second)
Name Stage Failure
failed
test:linux Test
../sysroot/lib/libc.a(c-0f9050933325baf2.c14-eb3f8c7e7944ec6c8e01560534fdf2c.rs.rcgu.o): In function `relibc_start':
c14-eb3f8c7e7944ec6c8e01560534fdf2c.rs:(.text.relibc_start+0x1d9): undefined reference to `_init'
collect2: error: ld returned 1 exit status
Makefile:151: recipe for target 'bins/args' failed
make[1]: Leaving directory '/builds/redox-os/relibc/tests'
make[1]: *** [bins/args] Error 1
make: *** [test] Error 2
Makefile:60: recipe for target 'test' failed
ERROR: Job failed: exit code 1
failed
fmt Test
+            set.clear();
+ }
+ if let Some(ref mut set) = exceptfds {
+ set.clear();
+ }

for event in &events[..read] {
if event.data == TIMEOUT_TOKEN {
ERROR: Job failed: exit code 1