Auto merge of #776 - snipsco:fix/ios-mangling, r=emilio

Fix iOS mangling

Hi,
We had a regression on a project that target iOS while upgrading bindgen from `0.25.3` to `0.25.4`.

After a long investigation it appeared that iOS need also a mangling hack. I managed to make a patch and successfully test it.

Thanks a lot for all your work.
Cheers

src/ir/context.rs

@@ -261,14 +261,15 @@ impl<'ctx> BindgenContext<'ctx> {
             effective_target = Some(HOST_TARGET.to_owned());
         }
 
-        // Mac os and Win32 need __ for mangled symbols but rust will automatically
+        // Mac os, iOS and Win32 need __ for mangled symbols but rust will automatically
         // prepend the extra _.
         //
         // We need to make sure that we don't include __ because rust will turn into
         // ___.
         let effective_target = effective_target.unwrap();
         let needs_mangling_hack =
             effective_target.contains("darwin") ||
+            effective_target.contains("ios") ||
             effective_target == "i686-pc-win32";
 
         let root_module = Self::build_root_module(ItemId(0));

tests/expectations/tests/mangling-ios.rs

@@ -0,0 +1,9 @@
+/* automatically generated by rust-bindgen */
+
+
+#![allow(dead_code, non_snake_case, non_camel_case_types, non_upper_case_globals)]
+
+
+extern "C" {
+    pub fn foo();
+}

tests/headers/mangling-ios.h

@@ -0,0 +1,3 @@
+// bindgen-flags: -- --target=x86_64-apple-ios
+
+void foo();