Revert daemon removal

This reverts the removal of the call to libc::daemon and instead adds an
annotation to ignore the deprecation warnings on macos.

This will not be an issue in the future since macOS is only discouraging
the use of `daemon`, but I'm not aware of any intention to actually
remove it.

This fixes #2211.

font/src/darwin/mod.rs

@@ -622,7 +622,6 @@ mod tests {
                             101...150 => '~',
                             151...200 => '*',
                             201...255 => '#',
-                            _ => unreachable!(),
                         };
                         print!("{}", c);
                     }

src/util.rs

@@ -14,7 +14,6 @@
 
 use std::ffi::OsStr;
 use std::process::Command;
-use std::process::Stdio;
 use std::{cmp, io};
 
 #[cfg(not(windows))]
@@ -23,6 +22,8 @@ use std::os::unix::process::CommandExt;
 #[cfg(windows)]
 use std::os::windows::process::CommandExt;
 #[cfg(windows)]
+use std::process::Stdio;
+#[cfg(windows)]
 use winapi::um::winbase::{CREATE_NEW_PROCESS_GROUP, CREATE_NO_WINDOW};
 
 /// Threading utilities
@@ -90,13 +91,9 @@ where
 {
     Command::new(program)
         .args(args)
-        .stdin(Stdio::null())
-        .stdout(Stdio::null())
-        .stderr(Stdio::null())
         .before_exec(|| unsafe {
-            if ::libc::fork() != 0 {
+            #[allow(deprecated)]
-                std::process::exit(0);
+            libc::daemon(1, 0);
-            }
             Ok(())
         })
         .spawn()?