gccrs: Add gcc-check-target check-rust

This allows us to invoke the rust testsuite.

	* Makefile.def: Add Rust language.
	* Makefile.in: Regenerate via autogen.

Makefile.def

@@ -676,6 +676,7 @@ languages = { language=go;	gcc-check-target=check-go;
 languages = { language=d;	gcc-check-target=check-d;
 				lib-check-target=check-target-libphobos; };
 languages = { language=jit;	gcc-check-target=check-jit; };
+languages = { language=rust;	gcc-check-target=check-rust; };
 
 // Toplevel bootstrap
 bootstrap_stage = { id=1 ; };

Makefile.in

@@ -61237,6 +61237,14 @@ check-gcc-jit:
 	(cd gcc && $(MAKE) $(GCC_FLAGS_TO_PASS) check-jit);
 check-jit: check-gcc-jit
+.PHONY: check-gcc-rust check-rust
+check-gcc-rust:
+	r=`${PWD_COMMAND}`; export r; \
+	s=`cd $(srcdir); ${PWD_COMMAND}`; export s; \
+	$(HOST_EXPORTS) \
+	(cd gcc && $(MAKE) $(GCC_FLAGS_TO_PASS) check-rust);
+check-rust: check-gcc-rust
+
 # The gcc part of install-no-fixedincludes, which relies on an intimate
 # knowledge of how a number of gcc internal targets (inter)operate.  Delegate.