The `make install` script, which most users would run via `sudo` to install into `/usr/local`, will use the current umask of the root user when creating certain files and directories. If one uses a restrictive umask by default (e.g. `umask 077`), this means that only the root user will be able to use the full Bitcoin package.

**Expected behavior**

The install script creates all directories and files, including man pages, etc., with permissions `644` / `755`.

**Actual behavior**

Certain folders are created using the default umask, e.g.:

- /usr/local/share/man/man1/
- /usr/local/lib/pkgconfig/
- [...]

This means that only root can access files in these folders and other users won't be able to read the man pages (for example).

**To reproduce**

```bash
$ ./autogen.sh
$ make
$ sudo -iu root
% umask 077
% make install
```

**System information**

OS: Linux
bitcoind version: HEAD
{
#if HAVE_SYSTEM
    ShutdownNotify(*node.args);
#endif
    InterruptHTTPServer();
    InterruptHTTPRPC();
    InterruptRPC();
    InterruptREST();
    InterruptTorControl();
    InterruptMapPort();
    if (node.connman)
        node.connman->Interrupt();
    if (g_txindex) {
        g_txindex->Interrupt();
    }
    ForEachBlockFilterIndex([](BlockFilterIndex& index) { index.Interrupt(); });
    if (g_coin_stats_index) {
        g_coin_stats_index->Interrupt();
    }
}
void Shutdown(NodeContext& node)