gccrs: Add option_env! support

gcc/rust/ChangeLog:
	* expand/rust-macro-builtins-utility.cc: Add macro expansion for
	option_env with eager expansion
	* expand/rust-macro-builtins.cc: Add option_env to builtin list
	* expand/rust-macro-builtins.h: Add option_env handler to header
	file
	* resolve/rust-late-name-resolver-2.0.cc: Prevent NR2.0 from
	recursing into lang-item segments

gcc/testsuite/ChangeLog:
	* rust/compile/macros/builtin/option_env1.rs: Add success case for option_env
	* rust/compile/macros/builtin/option_env2.rs: Add failure case for option_env
	* rust/execute/torture/builtin_macro_option_env.rs: Add
	execution case for option_env

1 files changed, 65 insertions, 0 deletions

diff --git a/gcc/testsuite/rust/execute/torture/builtin_macro_option_env.rs b/gcc/testsuite/rust/execute/torture/builtin_macro_option_env.rs
new file mode 100644
index 0000000..56fbeaa
--- /dev/null
+++ b/gcc/testsuite/rust/execute/torture/builtin_macro_option_env.rs
@@ -0,0 +1,65 @@
+// { dg-output "VALUE\r*\nVALUE\r*\n" }
+// { dg-set-compiler-env-var ENV_MACRO_TEST "VALUE" }
+
+#![feature(rustc_attrs)]
+
+#[rustc_builtin_macro]
+macro_rules! option_env {
+    () => {{}};
+}
+
+#[lang = "sized"]
+trait Sized {}
+
+pub mod core {
+    pub mod option {
+        pub enum Option<T> {
+            #[lang = "Some"]
+            Some(T),
+            #[lang = "None"]
+            None,
+        }
+    }
+}
+
+use core::option::Option;
+
+extern "C" {
+    fn printf(fmt: *const i8, ...);
+}
+
+fn print(s: &str) {
+    unsafe {
+        printf(
+            "%s\n" as *const str as *const i8,
+            s as *const str as *const i8,
+        );
+    }
+}
+
+macro_rules! env_macro_test {
+    () => { "ENV_MACRO_TEST" }
+}
+
+fn main() -> i32 {
+    let val0: Option<&'static str> = option_env!("ENV_MACRO_TEST");
+
+    
+    match val0 {
+        Option::None => {},
+        Option::Some(s) => {
+            print(s);
+        }
+    }
+
+    //eager expansion test
+    let val1: Option<&'static str> = option_env!(env_macro_test!(),);
+
+    match val1 {
+        Option::None => {},
+        Option::Some(s) => {
+            print(s);
+        }
+    }
+    0
+}