[fusl] Remove socketcall abstraction

fusl/src/network/socketpair.c

 #include <sys/socket.h>
 #include <fcntl.h>
 #include <errno.h>
 #include "syscall.h"
 
 int socketpair(int domain, int type, int protocol, int fd[2]) {
-  int r = socketcall(socketpair, domain, type, protocol, fd, 0, 0);
+  int r = syscall(SYS_socketpair, domain, type, protocol, fd, 0, 0);
   if (r < 0 && (errno == EINVAL || errno == EPROTONOSUPPORT) &&
       (type & (SOCK_CLOEXEC | SOCK_NONBLOCK))) {
-    r = socketcall(socketpair, domain, type & ~(SOCK_CLOEXEC | SOCK_NONBLOCK),
-                   protocol, fd, 0, 0);
+    r = syscall(SYS_socketpair, domain, type & ~(SOCK_CLOEXEC | SOCK_NONBLOCK),
+                protocol, fd, 0, 0);
     if (r < 0)
       return r;
     if (type & SOCK_CLOEXEC) {
       __syscall(SYS_fcntl, fd[0], F_SETFD, FD_CLOEXEC);
       __syscall(SYS_fcntl, fd[1], F_SETFD, FD_CLOEXEC);
     }
     if (type & SOCK_NONBLOCK) {
       __syscall(SYS_fcntl, fd[0], F_SETFL, O_NONBLOCK);
       __syscall(SYS_fcntl, fd[1], F_SETFL, O_NONBLOCK);
     }
   }
   return r;
 }