Bug 1444141 - part 4 - make the JS engine depend on Rust; r=chmanchester,glandium,jorendorff

The Rust dependency in Firefox has been limited to Firefox builds by
virtue of having the Rust check in a Firefox-specific location,
toolkit/moz.configure.  For JS to start depending on Rust, we need to
move that check to a location where a standalone JS engine build will
pick up the Rust check.

js/moz.configure

@@ -18,6 +18,9 @@ def building_js(build_project, help):
 option(env='JS_STANDALONE', default=building_js,
        help='Reserved for internal use')
 
+include('../build/moz.configure/rust.configure',
+        when='--enable-compile-environment')
+
 @depends('JS_STANDALONE')
 def js_standalone(value):
     if value:

moz.configure

@@ -141,7 +141,7 @@ include('build/moz.configure/warnings.configure',
         when='--enable-compile-environment')
 include('build/moz.configure/flags.configure',
         when='--enable-compile-environment')
-
+# rust.configure is included by js/moz.configure.
 
 js_option('--enable-valgrind',
           help='Enable Valgrind integration hooks')

old-configure.in

@@ -4658,6 +4658,7 @@ export MOZ_APP_NAME
 export MOZ_APP_REMOTINGNAME
 export MOZ_DEV_EDITION
 export RUSTC
+export CARGO
 export MOZILLA_CENTRAL_PATH=$_topsrcdir
 export STLPORT_CPPFLAGS
 export STLPORT_LIBS

toolkit/moz.configure

@@ -94,11 +94,6 @@ set_define('MOZ_PULSEAUDIO', depends_if(pulseaudio)(lambda _: True))
 include('../js/moz.configure')
 
 
-# Rust
-# ==============================================================
-include('../build/moz.configure/rust.configure',
-        when='--enable-compile-environment')
-
 # NodeJS
 # ==============================================================
 include('../build/moz.configure/node.configure')