basic/macros: rename noreturn into _noreturn_ (#8456)

"noreturn" is reserved and can be used in other header files we include:

  [   16s] In file included from /usr/include/gcrypt.h:30:0,
  [   16s]                  from ../src/journal/journal-file.h:26,
  [   16s]                  from ../src/journal/journal-vacuum.c:31:
  [   16s] /usr/include/gpg-error.h:1544:46: error: expected ‘,’ or ‘;’ before ‘)’ token
  [   16s]  void gpgrt_log_bug (const char *fmt, ...)    GPGRT_ATTR_NR_PRINTF(1,2);

Here we include grcrypt.h (which in turns include gpg-error.h) *after* we
"noreturn" was defined in macro.h.

src/basic/macro.h

@@ -53,6 +53,15 @@
 #else
 #define _fallthrough_
 #endif
+/* Define C11 noreturn without <stdnoreturn.h> and even on older gcc
+ * compiler versions */
+#ifndef _noreturn_
+#if __STDC_VERSION__ >= 201112L
+#define _noreturn_ _Noreturn
+#else
+#define _noreturn_ __attribute__((noreturn))
+#endif
+#endif
 
 /* Temporarily disable some warnings */
 #define DISABLE_WARNING_DECLARATION_AFTER_STATEMENT                     \
@@ -414,16 +423,6 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
 #endif
 #endif
 
-/* Define C11 noreturn without <stdnoreturn.h> and even on older gcc
- * compiler versions */
-#ifndef noreturn
-#if __STDC_VERSION__ >= 201112L
-#define noreturn _Noreturn
-#else
-#define noreturn __attribute__((noreturn))
-#endif
-#endif
-
 #define DEFINE_TRIVIAL_CLEANUP_FUNC(type, func)                 \
         static inline void func##p(type *p) {                   \
                 if (*p)                                         \