Auto merge of #139 - servo:cross-android, r=asajeffrey

Fix macOS/Android cross-compile.

These changes allow my local Servo android build to complete.

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Author: bors-servo

Cargo.toml

@@ -2,7 +2,7 @@
 name = "mozjs_sys"
 description = "System crate for the Mozilla SpiderMonkey JavaScript engine."
 repository = "https://github.com/servo/mozjs/"
-version = "0.51.1"
+version = "0.51.2"
 authors = ["Mozilla"]
 links = "mozjs"
 build = "build.rs"
@@ -29,3 +29,6 @@ libz-sys = "1.0"
 [build-dependencies]
 bindgen = "0.36.1"
 cc = "1.0"
+
+[patch.crates-io]
+libloading = { git = "https://github.com/servo/rust_libloading", branch = "mac-crash-revert" }

build.rs

@@ -122,6 +122,14 @@ fn build_jsglue() {
         build.flag_if_supported(flag);
     }
 
+    let config = format!("{}/js/src/js-confdefs.h", out.display());
+    if cfg!(windows) {
+        build.flag("-FI");
+    } else {
+        build.flag("-include");
+    }
+    build.flag(&config);
+
     build.file("src/jsglue.cpp");
     build.include(out.join("dist/include"));
     build.compile("jsglue");
@@ -161,14 +169,19 @@ fn build_jsapi_bindings() {
 
     if let Ok(flags) = env::var("CXXFLAGS") {
         for flag in flags.split_whitespace() {
-            builder = builder.clang_arg(flag);
+            if !flag.starts_with("--sysroot") {
+                builder = builder.clang_arg(flag);
+            }
         }
     }
 
     for flag in cc_flags() {
         builder = builder.clang_arg(flag);
     }
 
+    builder = builder.clang_arg("-include");
+    builder = builder.clang_arg(out.join("js/src/js-confdefs.h").to_str().expect("UTF-8"));
+
     println!("Generting bindings {:?}.", builder.command_line_flags());
 
     for ty in UNSAFE_IMPL_SYNC_TYPES {