maint: use gnulib _Noreturn rather than __attribute__ ((noreturn))

* src/grep.h (__attribute__): Remove.
* src/dfa.h (__attribute__): Likewise.
(dfaerror): Use noreturn rather than __attribute__ ((noreturn)).
* src/main.c (usage): Likewise.

3 files changed, 2 insertions, 10 deletions

diff --git a/src/dfa.h b/src/dfa.h
index 17a47786..351a4707 100644
--- a/src/dfa.h
+++ b/src/dfa.h
@@ -18,10 +18,6 @@
 
 /* Written June, 1988 by Mike Haertel */
 
-#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 6) || __STRICT_ANSI__
-# define __attribute__(x)
-#endif
-
 /* Element of a list of strings, at least one of which is known to
    appear in any R.E. matching the DFA. */
 struct dfamust
@@ -99,4 +95,4 @@ extern void dfawarn (const char *);
 /* dfaerror() is called by the regexp routines whenever an error occurs.  It
    takes a single argument, a NUL-terminated string describing the error.
    The user must supply a dfaerror.  */
-extern void dfaerror (const char *) __attribute__ ((noreturn));
+extern _Noreturn void dfaerror (const char *);
diff --git a/src/grep.h b/src/grep.h
index 744a8892..f5ab8bfc 100644
--- a/src/grep.h
+++ b/src/grep.h
@@ -20,10 +20,6 @@
 #ifndef GREP_GREP_H
 #define GREP_GREP_H 1
 
-#if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 6) || __STRICT_ANSI__
-# define __attribute__(x)
-#endif
-
 /* Function pointer types.  */
 typedef void (*compile_fp_t) (char const *, size_t);
 typedef size_t (*execute_fp_t) (char const *, size_t, size_t *, char const *);
diff --git a/src/main.c b/src/main.c
index e5938715..6151cacf 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1432,7 +1432,7 @@ grepdir (char const *dir, struct stats const *stats)
   return status;
 }
 
-void usage (int status) __attribute__ ((noreturn));
+_Noreturn void usage (int);
 void
 usage (int status)
 {