fix: builds on FreeBSD once again

The resource limis feature seems to be available only on certain platforms,
so the set_resource_limit() function and its test are enabled only on the
platforms that are known to be supported (linux and macos).

cargo test passes

src/wand/magick.rs

@@ -73,7 +73,8 @@ impl MagickWand {
         }
     }
 
-    #[cfg(not(windows))]
+    // opt-in platforms that have resource limits support
+    #[cfg(any(target_os = "linux", target_os = "macos"))]
     pub fn set_resource_limit(resource: ResourceType, limit: u64) -> Result<()> {
         let result = unsafe {
             bindings::SetMagickResourceLimit(