Fix -Wshift-negative-value warnings with MAKE_PROCESS_CPUCLOCK.

linux_syscall_support.h

Index: linux_syscall_support.h
diff --git a/linux_syscall_support.h b/linux_syscall_support.h
index 9dbd2391b2e3825731833714a81feb896ddfef46..ae6e50ae36ee36462b5f4cf317cdce7ba85ca2df 100644
--- a/linux_syscall_support.h
+++ b/linux_syscall_support.h
@@ -727,11 +727,12 @@ struct kernel_statfs {
 #endif
 #ifndef MAKE_PROCESS_CPUCLOCK
 #define MAKE_PROCESS_CPUCLOCK(pid, clock)                                     \
-        ((~(int)(pid) << 3) | (int)(clock))
+        ((int)(~(unsigned)(pid) << 3) | (int)(clock))
 #endif
 #ifndef MAKE_THREAD_CPUCLOCK
 #define MAKE_THREAD_CPUCLOCK(tid, clock)                                      \
-        ((~(int)(tid) << 3) | (int)((clock) | CPUCLOCK_PERTHREAD_MASK))
+        ((int)(~(unsigned)(tid) << 3) |                                       \
+         (int)((clock) | CPUCLOCK_PERTHREAD_MASK))
 #endif
 
 #ifndef FUTEX_WAIT