diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 53ad59b1b160..5929dde23095 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -321,9 +321,19 @@ pub const ATF_PUBL: ::c_int = 0x08;
 pub const ATF_USETRAILERS: ::c_int = 0x10;
 
 pub const FNM_PERIOD: c_int = 1 << 2;
-pub const FNM_CASEFOLD: c_int = 1 << 4;
 pub const FNM_NOMATCH: c_int = 1;
 
+cfg_if! {
+    if #[cfg(any(
+        target_os = "illumos",
+        target_os = "solaris",
+    ))] {
+        pub const FNM_CASEFOLD: c_int = 0x08;
+    } else {
+        pub const FNM_CASEFOLD: c_int = 1 << 4;
+    }
+}
+
 cfg_if! {
     if #[cfg(any(
         target_os = "macos",