fix: build for freebsd (reubeno#980)

Also sets FD_DIR_PATH for other BSD distros.

Author: tmfink

brush-core/src/sys/unix/fd.rs

@@ -4,17 +4,36 @@ use std::os::fd::RawFd;
 
 use crate::{ShellFd, error, openfiles};
 
-#[cfg(target_os = "linux")]
-const FD_DIR_PATH: &str = "/proc/self/fd";
-
-#[cfg(target_os = "macos")]
-const FD_DIR_PATH: &str = "/dev/fd";
+cfg_if::cfg_if! {
+    if #[cfg(target_os = "linux")] {
+        const FD_DIR_PATH: &str = "/proc/self/fd";
+    } else if #[cfg(any(
+            target_os = "freebsd",
+            target_os = "macos",
+            target_os = "netbsd",
+            target_os = "openbsd"
+        ))] {
+        const FD_DIR_PATH: &str = "/dev/fd";
+    } else {
+        pub fn iter_fds()
+        -> Result<impl Iterator<Item = (ShellFd, openfiles::OpenFile)>, error::Error> {
+            Ok(std::iter::empty())
+        }
+    }
+}
 
 /// Makes a best-effort attempt to iterate over all open file descriptors
 /// for the current process.
 ///
 /// If the platform does not support enumerating file descriptors, an empty iterator
 /// is returned. This function will skip any file descriptors that cannot be opened.
+#[cfg(any(
+    target_os = "freebsd",
+    target_os = "linux",
+    target_os = "macos",
+    target_os = "netbsd",
+    target_os = "openbsd"
+))]
 pub fn try_iter_open_fds() -> impl Iterator<Item = (ShellFd, openfiles::OpenFile)> {
     let mut opened_entries = vec![];
 
@@ -40,11 +59,6 @@ pub fn try_iter_open_fds() -> impl Iterator<Item = (ShellFd, openfiles::OpenFile
     opened_entries.into_iter()
 }
 
-#[cfg(not(any(target_os = "linux", target_os = "macos")))]
-pub fn iter_fds() -> Result<impl Iterator<Item = (ShellFd, openfiles::OpenFile)>, error::Error> {
-    Ok(std::iter::empty())
-}
-
 /// Attempts to retrieve an `OpenFile` representation for the given already-open file descriptor.
 ///
 /// If the file descriptor cannot be opened, `None` is returned. Note that there is no guarantee