Fix warnings

This change fixes Cosmopolitan so it has fewer opinions about compiler
warnings. The whole repository had to be cleaned up to be buildable in
-Werror -Wall mode. This lets us benefit from things like strict const
checking. Some actual bugs might have been caught too.

test/libc/thread/pthread_cancel_test.c

@@ -68,7 +68,6 @@ TEST(pthread_cancel, self_deferred_waitsForCancellationPoint) {
 }
 
 void *Worker(void *arg) {
-  int n;
   char buf[8];
   pthread_cleanup_push(OnCleanup, 0);
   read(pfds[0], buf, sizeof(buf));
@@ -224,8 +223,10 @@ void *CpuBoundWorker(void *arg) {
   CheckStackIsAligned();
   wouldleak = malloc(123);
   wontleak1 = malloc(123);
+  (void)wontleak1;
   pthread_cleanup_push(free, wontleak1);
   wontleak2 = _gc(malloc(123));
+  (void)wontleak2;
   ASSERT_EQ(0, pthread_setspecific(key, (void *)31337));
   ASSERT_EQ(0, pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0));
 #ifdef __x86_64__
@@ -262,7 +263,6 @@ TEST(pthread_cancel, async) {
 }
 
 void *CancelSelfWorkerAsync(void *arg) {
-  char buf[8];
   pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, 0);
   pthread_cleanup_push(OnCleanup, 0);
   pthread_cancel(pthread_self());

test/libc/thread/pthread_create_test.c

@@ -40,7 +40,6 @@
 #include "libc/thread/thread2.h"
 
 void OnUsr1(int sig, struct siginfo *si, void *vctx) {
-  struct ucontext *ctx = vctx;
 }
 
 void SetUp(void) {
@@ -83,7 +82,7 @@ TEST(pthread_create, testCreateExitJoin) {
 }
 
 static void *CheckSchedule(void *arg) {
-  int rc, policy;
+  int policy;
   struct sched_param prio;
   ASSERT_EQ(0, pthread_getschedparam(pthread_self(), &policy, &prio));
   ASSERT_EQ(SCHED_OTHER, policy);

test/libc/thread/pthread_detach_test.c

@@ -27,7 +27,6 @@
 #include "libc/thread/thread.h"
 
 void OnUsr1(int sig, struct siginfo *si, void *vctx) {
-  struct ucontext *ctx = vctx;
 }
 
 void SetUp(void) {

test/libc/thread/sem_timedwait_test.c

@@ -17,6 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
+#include "libc/calls/struct/sigaction.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/dce.h"
 #include "libc/errno.h"
@@ -44,54 +45,53 @@ TEST(sem_init, einval) {
 
 TEST(sem_post, afterDestroyed_isUndefinedBehavior) {
   if (!IsModeDbg()) return;
-  int val;
   sem_t sem;
   SPAWN(fork);
+  signal(SIGABRT, SIG_DFL);
   ASSERT_SYS(0, 0, sem_init(&sem, 0, 0));
   ASSERT_SYS(0, 0, sem_destroy(&sem));
   IgnoreStderr();
   sem_post(&sem);
-  EXITS(128 + SIGABRT);  // see __assert_fail
+  TERMS(SIGABRT);
 }
 
 TEST(sem_trywait, afterDestroyed_isUndefinedBehavior) {
   if (!IsModeDbg()) return;
-  int val;
   sem_t sem;
   SPAWN(fork);
+  signal(SIGABRT, SIG_DFL);
   ASSERT_SYS(0, 0, sem_init(&sem, 0, 0));
   ASSERT_SYS(0, 0, sem_destroy(&sem));
   IgnoreStderr();
   sem_trywait(&sem);
-  EXITS(128 + SIGABRT);  // see __assert_fail
+  TERMS(SIGABRT);
 }
 
 TEST(sem_wait, afterDestroyed_isUndefinedBehavior) {
   if (!IsModeDbg()) return;
-  int val;
   sem_t sem;
   SPAWN(fork);
+  signal(SIGABRT, SIG_DFL);
   ASSERT_SYS(0, 0, sem_init(&sem, 0, 0));
   ASSERT_SYS(0, 0, sem_destroy(&sem));
   IgnoreStderr();
   sem_wait(&sem);
-  EXITS(128 + SIGABRT);  // see __assert_fail
+  TERMS(SIGABRT);
 }
 
 TEST(sem_timedwait, afterDestroyed_isUndefinedBehavior) {
   if (!IsModeDbg()) return;
-  int val;
   sem_t sem;
   SPAWN(fork);
+  signal(SIGABRT, SIG_DFL);
   ASSERT_SYS(0, 0, sem_init(&sem, 0, 0));
   ASSERT_SYS(0, 0, sem_destroy(&sem));
   IgnoreStderr();
   sem_timedwait(&sem, 0);
-  EXITS(128 + SIGABRT);  // see __assert_fail
+  TERMS(SIGABRT);
 }
 
 void *Worker(void *arg) {
-  int rc;
   sem_t **s = arg;
   struct timespec ts;
   ASSERT_SYS(0, 0, clock_gettime(CLOCK_REALTIME, &ts));