Improve cosmo's conformance to libc-test

This change addresses various open source compatibility issues, so that
we pass 313/411 of the tests in https://github.com/jart/libc-test where
earlier today we were passing about 30/411 of them, due to header toil.
Please note that Glibc only passes 341/411 so 313 today is pretty good!

- Make the conformance of libc/isystem/ headers nearly perfect
- Import more of the remaining math library routines from Musl
- Fix inconsistencies with type signatures of calls like umask
- Write tests for getpriority/setpriority which work great now
- conform to `struct sockaddr *` on remaining socket functions
- Import a bunch of uninteresting stdlib functions e.g. rand48
- Introduce readdir_r, scandir, pthread_kill, sigsetjmp, etc..

Follow the instructions in our `tool/scripts/cosmocc` toolchain to run
these tests yourself. You use `make CC=cosmocc` on the test repository

tool/build/lib/syscall.c

@@ -40,13 +40,14 @@
 #include "libc/log/check.h"
 #include "libc/log/log.h"
 #include "libc/macros.internal.h"
+#include "libc/mem/gc.internal.h"
 #include "libc/mem/mem.h"
 #include "libc/nexgen32e/vendor.internal.h"
-#include "libc/mem/gc.internal.h"
 #include "libc/runtime/pc.internal.h"
 #include "libc/runtime/runtime.h"
 #include "libc/sock/select.h"
 #include "libc/sock/sock.h"
+#include "libc/sock/struct/sockaddr.h"
 #include "libc/str/str.h"
 #include "libc/sysv/consts/af.h"
 #include "libc/sysv/consts/at.h"
@@ -485,7 +486,7 @@ static int OpAccept4(struct Machine *m, int fd, int64_t aa, int64_t asa,
 }
 
 static int OpConnectBind(struct Machine *m, int fd, int64_t aa, uint32_t as,
-                         int impl(int, const void *, uint32_t)) {
+                         int impl(int, const struct sockaddr *, uint32_t)) {
   struct sockaddr_in addr;
   struct sockaddr_in_bits gaddr;
   if (as != sizeof(gaddr)) return einval();
@@ -540,7 +541,7 @@ static int OpGetsockopt(struct Machine *m, int fd, int level, int optname,
 }
 
 static int OpSocketName(struct Machine *m, int fd, int64_t aa, int64_t asa,
-                        int SocketName(int, void *, socklen_t *)) {
+                        int SocketName(int, struct sockaddr *, socklen_t *)) {
   int rc;
   uint32_t addrsize;
   uint8_t gaddrsize[4];

tool/build/runitd.c

@@ -216,12 +216,13 @@ void StartTcpServer(void) {
   setsockopt(g_servfd, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
 
   LOGIFNEG1(setsockopt(g_servfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes)));
-  if (bind(g_servfd, &g_servaddr, sizeof(g_servaddr)) == -1) {
+  if (bind(g_servfd, (struct sockaddr *)&g_servaddr, sizeof(g_servaddr)) ==
+      -1) {
     FATALF("bind failed %m");
   }
   CHECK_NE(-1, listen(g_servfd, 10));
   asize = sizeof(g_servaddr);
-  CHECK_NE(-1, getsockname(g_servfd, &g_servaddr, &asize));
+  CHECK_NE(-1, getsockname(g_servfd, (struct sockaddr *)&g_servaddr, &asize));
   INFOF("%s:%s", "listening on tcp", _gc(DescribeAddress(&g_servaddr)));
   if (g_sendready) {
     printf("ready %hu\n", ntohs(g_servaddr.sin_port));
@@ -374,7 +375,8 @@ void HandleClient(void) {
   addrsize = sizeof(addr);
   INFOF("accept");
   do {
-    g_clifd = accept4(g_servfd, &addr, &addrsize, SOCK_CLOEXEC);
+    g_clifd =
+        accept4(g_servfd, (struct sockaddr *)&addr, &addrsize, SOCK_CLOEXEC);
   } while (g_clifd == -1 && errno == EAGAIN);
   CHECK_NE(-1, g_clifd);
   if (fork()) {

tool/net/echo.c

@@ -54,21 +54,22 @@ void UdpServer(void) {
   struct sockaddr_in addr2;
   uint32_t addrsize2 = sizeof(struct sockaddr_in);
   CHECK_NE(-1, (sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)));
-  CHECK_NE(-1, bind(sock, &addr, addrsize));
-  CHECK_NE(-1, getsockname(sock, &addr2, &addrsize2));
+  CHECK_NE(-1, bind(sock, (struct sockaddr *)&addr, addrsize));
+  CHECK_NE(-1, getsockname(sock, (struct sockaddr *)&addr2, &addrsize2));
   ip = ntohl(addr2.sin_addr.s_addr);
   kprintf("udp server %hhu.%hhu.%hhu.%hhu %hu%n", ip >> 24, ip >> 16, ip >> 8,
           ip, ntohs(addr2.sin_port));
   for (;;) {
+    CHECK_NE(-1, (rc = recvfrom(sock, buf, sizeof(buf), 0,
+                                (struct sockaddr *)&addr2, &addrsize2)));
     CHECK_NE(-1,
-             (rc = recvfrom(sock, buf, sizeof(buf), 0, &addr2, &addrsize2)));
-    CHECK_NE(-1, sendto(sock, buf, rc, 0, &addr2, addrsize2));
+             sendto(sock, buf, rc, 0, (struct sockaddr *)&addr2, addrsize2));
   }
 }
 
 void UdpClient(void) {
   CHECK_NE(-1, (sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)));
-  CHECK_NE(-1, connect(sock, &addr, addrsize));
+  CHECK_NE(-1, connect(sock, (struct sockaddr *)&addr, addrsize));
   for (;;) {
     rngset(buf, sizeof(buf), _rand64, -1);
     CHECK_NE(-1, write(sock, &addr, addrsize));
@@ -81,9 +82,9 @@ void TcpServer(void) {
   struct sockaddr_in addr2;
   uint32_t addrsize2 = sizeof(struct sockaddr_in);
   CHECK_NE(-1, (sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)));
-  CHECK_NE(-1, bind(sock, &addr, addrsize));
+  CHECK_NE(-1, bind(sock, (struct sockaddr *)&addr, addrsize));
   CHECK_NE(-1, listen(sock, 10));
-  CHECK_NE(-1, getsockname(sock, &addr2, &addrsize2));
+  CHECK_NE(-1, getsockname(sock, (struct sockaddr *)&addr2, &addrsize2));
   ip = ntohl(addr2.sin_addr.s_addr);
   kprintf("tcp server %hhu.%hhu.%hhu.%hhu %hu%n", ip >> 24, ip >> 16, ip >> 8,
           ip, ntohs(addr2.sin_port));
@@ -104,7 +105,7 @@ void TcpServer(void) {
 
 void TcpClient(void) {
   CHECK_NE(-1, (sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)));
-  CHECK_NE(-1, connect(sock, &addr, addrsize));
+  CHECK_NE(-1, connect(sock, (struct sockaddr *)&addr, addrsize));
   for (;;) {
     rngset(buf, sizeof(buf), _rand64, -1);
     CHECK_NE(-1, write(sock, buf, sizeof(buf)));

tool/net/redbean.c

@@ -6492,8 +6492,8 @@ static void MonitorMemory(void) {
 static int HandleConnection(size_t i) {
   int pid, rc = 0;
   clientaddrsize = sizeof(clientaddr);
-  if ((client = accept4(servers.p[i].fd, &clientaddr, &clientaddrsize,
-                        SOCK_CLOEXEC)) != -1) {
+  if ((client = accept4(servers.p[i].fd, (struct sockaddr *)&clientaddr,
+                        &clientaddrsize, SOCK_CLOEXEC)) != -1) {
     startconnection = _timespec_real();
     if (UNLIKELY(maxworkers) && shared->workers >= maxworkers) {
       EnterMeltdownMode();
@@ -6776,7 +6776,7 @@ static void Listen(void) {
         continue;
       }
 
-      if (bind(servers.p[n].fd, &servers.p[n].addr,
+      if (bind(servers.p[n].fd, (struct sockaddr *)&servers.p[n].addr,
                sizeof(servers.p[n].addr)) == -1) {
         DIEF("(srvr) bind error: %m: %hhu.%hhu.%hhu.%hhu:%hu", ips.p[i] >> 24,
              ips.p[i] >> 16, ips.p[i] >> 8, ips.p[i], ports.p[j]);
@@ -6785,7 +6785,8 @@ static void Listen(void) {
         DIEF("(srvr) listen error: %m");
       }
       addrsize = sizeof(servers.p[n].addr);
-      if (getsockname(servers.p[n].fd, &servers.p[n].addr, &addrsize) == -1) {
+      if (getsockname(servers.p[n].fd, (struct sockaddr *)&servers.p[n].addr,
+                      &addrsize) == -1) {
         DIEF("(srvr) getsockname error: %m");
       }
       port = ntohs(servers.p[n].addr.sin_port);