Port a lot more code to AARCH64

- Introduce epoll_pwait()
- Rewrite -ftrapv and ffs() libraries in C code
- Use more FreeBSD code in math function library
- Get significantly more tests passing on qemu-aarch64
- Fix many Musl long double functions that were broken on AARCH64

libc/sock/epoll.c

@@ -36,7 +36,9 @@
 #include "libc/assert.h"
 #include "libc/calls/cp.internal.h"
 #include "libc/calls/internal.h"
+#include "libc/calls/sig.internal.h"
 #include "libc/calls/state.internal.h"
+#include "libc/calls/struct/sigset.internal.h"
 #include "libc/calls/syscall_support-sysv.internal.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
@@ -71,10 +73,9 @@
 #include "libc/sock/internal.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/epoll.h"
+#include "libc/sysv/consts/sig.h"
 #include "libc/sysv/errfuns.h"
 
-#ifdef __x86_64__
-
 /**
  * @fileoverview epoll
  *
@@ -1520,10 +1521,15 @@ int epoll_ctl(int epfd, int op, int fd, struct epoll_event *ev) {
  */
 int epoll_wait(int epfd, struct epoll_event *events, int maxevents,
                int timeoutms) {
-  int rc;
+  int e, rc;
   BEGIN_CANCELLATION_POINT;
   if (!IsWindows()) {
+    e = errno;
     rc = sys_epoll_wait(epfd, events, maxevents, timeoutms);
+    if (rc == -1 && errno == ENOSYS) {
+      errno = e;
+      rc = sys_epoll_pwait(epfd, events, maxevents, timeoutms, 0, 0);
+    }
   } else {
     rc = sys_epoll_wait_nt(epfd, events, maxevents, timeoutms);
   }
@@ -1533,4 +1539,39 @@ int epoll_wait(int epfd, struct epoll_event *events, int maxevents,
   return rc;
 }
 
-#endif /* __x86_64__ */
+/**
+ * Receives socket events.
+ *
+ * @param events will receive information about what happened
+ * @param maxevents is array length of events
+ * @param timeoutms is milliseconds, 0 to not block, or -1 for forever
+ * @param sigmask is an optional sigprocmask() to use during call
+ * @return number of events stored, 0 on timeout, or -1 w/ errno
+ * @cancellationpoint
+ * @norestart
+ */
+int epoll_pwait(int epfd, struct epoll_event *events, int maxevents,
+                int timeoutms, const sigset_t *sigmask) {
+  int e, rc;
+  sigset_t oldmask;
+  BEGIN_CANCELLATION_POINT;
+  if (!IsWindows()) {
+    e = errno;
+    rc = sys_epoll_pwait(epfd, events, maxevents, timeoutms, sigmask,
+                         sizeof(*sigmask));
+    if (rc == -1 && errno == ENOSYS) {
+      errno = e;
+      if (sigmask) sys_sigprocmask(SIG_SETMASK, sigmask, &oldmask);
+      rc = sys_epoll_wait(epfd, events, maxevents, timeoutms);
+      if (sigmask) sys_sigprocmask(SIG_SETMASK, &oldmask, 0);
+    }
+  } else {
+    if (sigmask) __sig_mask(SIG_SETMASK, sigmask, &oldmask);
+    rc = sys_epoll_wait_nt(epfd, events, maxevents, timeoutms);
+    if (sigmask) __sig_mask(SIG_SETMASK, &oldmask, 0);
+  }
+  END_CANCELLATION_POINT;
+  STRACE("epoll_pwait(%d, %p, %d, %d) → %d% m", epfd, events, maxevents,
+         timeoutms, DescribeSigset(0, sigmask), rc);
+  return rc;
+}

libc/sock/epoll.h

@@ -2,6 +2,7 @@
 #define COSMOPOLITAN_LIBC_SOCK_WEPOLL_H_
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
+#include "libc/calls/struct/sigset.h"
 
 typedef union epoll_data {
   void *ptr;
@@ -19,6 +20,7 @@ int epoll_create(int);
 int epoll_create1(int);
 int epoll_ctl(int, int, int, struct epoll_event *);
 int epoll_wait(int, struct epoll_event *, int, int);
+int epoll_pwait(int, struct epoll_event *, int, int, const sigset_t *);
 
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */

libc/sock/internal.h

@@ -1,6 +1,7 @@
 #ifndef COSMOPOLITAN_LIBC_SOCK_INTERNAL_H_
 #define COSMOPOLITAN_LIBC_SOCK_INTERNAL_H_
 #include "libc/calls/struct/iovec.h"
+#include "libc/calls/struct/sigset.h"
 #include "libc/nt/struct/overlapped.h"
 #include "libc/nt/thunk/msabi.h"
 #include "libc/nt/winsock.h"
@@ -79,6 +80,8 @@ int sys_setsockopt(int, int, int, const void *, uint32_t) _Hide;
 int32_t sys_epoll_create(int32_t) _Hide;
 int32_t sys_epoll_ctl(int32_t, int32_t, int32_t, void *) _Hide;
 int32_t sys_epoll_wait(int32_t, void *, int32_t, int32_t) _Hide;
+int32_t sys_epoll_pwait(int32_t, void *, int32_t, int32_t, const sigset_t *,
+                        size_t);
 
 int sys_socket_nt(int, int, int) _Hide;
 

libc/sock/nointernet.c

@@ -44,7 +44,6 @@
 #include "libc/sysv/consts/sig.h"
 #include "libc/sysv/errfuns.h"
 #include "net/http/ip.h"
-
 #ifdef __x86_64__
 
 #define ORIG_RAX 120