Add an example to check the flags are being stripped

Author: dae

examples/ios/BUILD.bazel

@@ -2,6 +2,7 @@ load("@build_bazel_rules_apple//apple:ios.bzl", "ios_application")
 load("@build_bazel_rules_apple//apple:macos.bzl", "macos_application")
 load("@rules_cc//cc:defs.bzl", "cc_library", "objc_library")
 load("@rules_rust//rust:defs.bzl", "rust_library")
+load("@rules_rust//cargo:cargo_build_script.bzl", "cargo_build_script")
 
 cc_library(
     name = "allocator_library",
@@ -90,3 +91,14 @@ platform(
         "@build_bazel_apple_support//constraints:device",
     ],
 )
+
+cargo_build_script(
+    name = "build_script",
+    srcs = ["build.rs"],
+)
+
+rust_library(
+    name = "build_script_consumer",
+    srcs = ["empty.rs"],
+    deps = [":build_script"],
+)

examples/ios/build.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let flags = std::env::var("CFLAGS").unwrap();
+    // the host architecture used to run the build script should not leak into the
+    // CFLAGS, or the build script may compile code for the wrong architecture
+    assert!(!flags.contains("-isysroot"));
+    assert!(!flags.contains("-target"));
+}

examples/ios/empty.rs

@@ -0,0 +1 @@
+