LibCore: Add syscall wrapper for ptsname()

Userland/Libraries/LibCore/System.cpp

@@ -187,4 +187,12 @@ ErrorOr<int> dup2(int source_fd, int destination_fd)
     return fd;
 }
 
+ErrorOr<String> ptsname(int fd)
+{
+    auto* name = ::ptsname(fd);
+    if (!name)
+        return Error::from_syscall("ptsname"sv, -errno);
+    return String(name);
+}
+
 }

Userland/Libraries/LibCore/System.h

@@ -31,5 +31,6 @@ ErrorOr<ssize_t> read(int fd, void* buffer, size_t buffer_size);
 ErrorOr<ssize_t> write(int fd, void const* data, size_t data_size);
 ErrorOr<void> kill(pid_t, int signal);
 ErrorOr<int> dup2(int source_fd, int destination_fd);
+ErrorOr<String> ptsname(int fd);
 
 }