Make signal handling work well across platforms

- Fix sigsuspend() on XNU
- Fix strsignal() on non-Linux
- Add unit tests for strsignal()
- Add unit tests for setitimer()
- Add unit tests for sigsuspend()
- Rewrite setitimer() for New Technology
- Rewrite nanosleep() for New Technology
- Polyfill SIGALRM on the New Technology
- select(0,0,0,0) on NT now calls pause()
- Remove some NTDLL calls that aren't needed
- Polyfill SA_NOCLDWAIT on the New Technology
- Polyfill SA_RESETHAND on the New Technology
- Polyfill sigprocmask() on the New Technology
- Polyfill SIGCHLD+SIG_IGN on the New Technology
- Polyfill SA_RESTART masking on the New Technology
- Deliver console signals from main thread on New Technology
- Document SA_RESTART behavior w/ @sarestartable / @norestart
- System call trace in MODE=dbg now prints inherited FDs and signal mask

libc/sock/epoll.c

@@ -1345,7 +1345,7 @@ static textwindows dontinline int sys_epoll_create1_nt(uint32_t flags) {
 }
 
 static textwindows dontinline int sys_epoll_ctl_nt(int epfd, int op, int fd,
-                                                 struct epoll_event *ev) {
+                                                   struct epoll_event *ev) {
   int r;
   struct PortState *port_state;
   struct TsTreeNode *tree_node;
@@ -1375,9 +1375,9 @@ static textwindows dontinline int sys_epoll_ctl_nt(int epfd, int op, int fd,
 }
 
 static textwindows dontinline int sys_epoll_wait_nt(int epfd,
-                                                  struct epoll_event *events,
-                                                  int maxevents,
-                                                  int timeoutms) {
+                                                    struct epoll_event *events,
+                                                    int maxevents,
+                                                    int timeoutms) {
   int num_events;
   struct PortState *port_state;
   struct TsTreeNode *tree_node;
@@ -1493,6 +1493,7 @@ int epoll_ctl(int epfd, int op, int fd, struct epoll_event *ev) {
  * @param maxevents is array length of events
  * @param timeoutms is milliseconds, 0 to not block, or -1 for forever
  * @return number of events stored, 0 on timeout, or -1 w/ errno
+ * @norestart
  */
 int epoll_wait(int epfd, struct epoll_event *events, int maxevents,
                int timeoutms) {