gccrs: Add all rust keywords (except priv) to the follow-set of `:vis` when parsing macro rules

Previously, the following macro rules were rejected by gccrs:
```Rust
macro_rules! {
    ($v:vis <KEY_WORD>) => { ... };
}
```

This PR fixes so the above code is accepted by the compiler for all key words like `async` or `unsafe`.
The only exception is the keyword `priv` which is not allowed.
See [this page](https://doc.rust-lang.org/reference/macro-ambiguity.html) for reference. Especially the following excerpt:
> FOLLOW(vis) = {,l any keyword or identifier except a non-raw priv; any token that can begin a type; ident, ty, and path nonterminals}.

Fixes #1060

gcc/rust/ChangeLog:

	* parse/rust-parse.cc: fix follow-sets

gcc/testsuite/ChangeLog:

	* rust/compile/macro47.rs: Test that :vis can be followed by some keywords
	* rust/compile/macro48.rs: Test that :vis cannot be followed by the keyword priv

Signed-off-by: Tage Johansson <frans.tage@gmail.com>

1 files changed, 64 insertions, 28 deletions

diff --git a/gcc/rust/parse/rust-parse.cc b/gcc/rust/parse/rust-parse.cc
index f1e2caa..1b565bc 100644
--- a/gcc/rust/parse/rust-parse.cc
+++ b/gcc/rust/parse/rust-parse.cc
@@ -17,6 +17,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "rust-parse.h"
 #include "rust-linemap.h"
 #include "rust-diagnostics.h"
+#include "rust-token.h"
 
 namespace Rust {
 
@@ -166,34 +167,69 @@ peculiar_fragment_match_compatible (const AST::MacroMatchFragment &last_match,
 	{MATCH_ARROW, COMMA, EQUAL, PIPE, SEMICOLON, COLON, RIGHT_ANGLE,
 	 RIGHT_SHIFT, LEFT_SQUARE, LEFT_CURLY, AS, WHERE}},
        {AST::MacroFragSpec::VIS,
-	{
-	  COMMA,
-	  IDENTIFIER /* FIXME: Other than `priv` */,
-	  LEFT_PAREN,
-	  LEFT_SQUARE,
-	  EXCLAM,
-	  ASTERISK,
-	  AMP,
-	  LOGICAL_AND,
-	  QUESTION_MARK,
-	  LIFETIME,
-	  LEFT_ANGLE,
-	  LEFT_SHIFT,
-	  SUPER,
-	  SELF,
-	  SELF_ALIAS,
-	  EXTERN_TOK,
-	  CRATE,
-	  UNDERSCORE,
-	  FOR,
-	  IMPL,
-	  FN_TOK,
-	  UNSAFE,
-	  TYPEOF,
-	  DYN
-	  // FIXME: Add Non kw identifiers
-	  // FIXME: Add $crate as valid
-	}}};
+	{COMMA,
+	 IDENTIFIER,
+	 LEFT_PAREN,
+	 LEFT_SQUARE,
+	 EXCLAM,
+	 ASTERISK,
+	 AMP,
+	 LOGICAL_AND,
+	 QUESTION_MARK,
+	 LIFETIME,
+	 LEFT_ANGLE,
+	 LEFT_SHIFT,
+	 UNDERSCORE,
+	 ABSTRACT,
+	 AS,
+	 ASYNC,
+	 AUTO,
+	 BECOME,
+	 BOX,
+	 BREAK,
+	 CONST,
+	 CONTINUE,
+	 CRATE,
+	 DO,
+	 DYN,
+	 ELSE,
+	 ENUM_TOK,
+	 EXTERN_TOK,
+	 FALSE_LITERAL,
+	 FINAL_TOK,
+	 FN_TOK,
+	 FOR,
+	 IF,
+	 IMPL,
+	 IN,
+	 LET,
+	 LOOP,
+	 MACRO,
+	 MATCH_TOK,
+	 MOD,
+	 MOVE,
+	 MUT,
+	 OVERRIDE_TOK,
+	 PUB,
+	 REF,
+	 RETURN_TOK,
+	 SELF_ALIAS,
+	 SELF,
+	 STATIC_TOK,
+	 STRUCT_TOK,
+	 SUPER,
+	 TRAIT,
+	 TRUE_LITERAL,
+	 TRY,
+	 TYPE,
+	 TYPEOF,
+	 UNSAFE,
+	 UNSIZED,
+	 USE,
+	 VIRTUAL,
+	 WHERE,
+	 WHILE,
+	 YIELD}}};
 
   Location error_locus = match.get_match_locus ();
   std::string kind_str = "fragment";