Make improvements

- Fix unused local variable errors
- Remove yoinks from sigaction() header
- Add nox87 and aarch64 to github actions
- Fix cosmocc -fportcosmo in linking mode
- It's now possible to build `make m=llvm o/llvm/libc`

libc/thread/makecontext.c

@@ -101,7 +101,7 @@ void makecontext(ucontext_t *uc, void func(), int argc, ...) {
   sp += uc->uc_stack.ss_size;
   sp -= 16;  // openbsd:stackbound
   sp -= sizeof(*call);
-  sp &= -alignof(*call);
+  sp &= -alignof(struct Gadget);
   call = (struct Gadget *)sp;
 
   // get arguments

libc/thread/pthread_getaffinity_np.c

@@ -38,10 +38,9 @@
  */
 errno_t pthread_getaffinity_np(pthread_t thread, size_t size,
                                cpu_set_t *bitset) {
-  int e, rc, tid;
+  int rc, tid;
 
   if (!(rc = pthread_getunique_np(thread, &tid))) {
-    e = errno;
     if (size != sizeof(cpu_set_t)) {
       rc = einval();
     } else if (IsWindows() || IsMetal() || IsOpenbsd()) {

libc/thread/sem_open.c

@@ -253,7 +253,7 @@ sem_t *sem_open(const char *name, int oflag, ...) {
  * @return 0 on success, or -1 w/ errno
  */
 int sem_close(sem_t *sem) {
-  int rc, prefs;
+  int prefs;
   bool unmap, delete;
   struct Semaphore *s, **p;
   _npassert(sem->sem_magic == SEM_MAGIC_NAMED);
@@ -275,7 +275,7 @@ int sem_close(sem_t *sem) {
     _npassert(!munmap(sem, PAGESIZE));
   }
   if (delete) {
-    rc = unlink(s->path);
+    unlink(s->path);
   }
   if (unmap) {
     free(s->path);

libc/thread/spawn.c

@@ -69,7 +69,7 @@ static int Spawner(void *arg, int tid) {
   rc = spawner->fun(spawner->arg, tid);
   _pthread_ungarbage();
   free(spawner);
-  return 0;
+  return rc;
 }
 
 /**