Make OPENSSL_die as noreturn

Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/526)

include/openssl/crypto.h

@@ -310,10 +310,10 @@ int CRYPTO_mem_leaks(BIO *bio);
 # endif
 
 /* die if we have to */
+ossl_noreturn void OPENSSL_die(const char *assertion, const char *file, int line);
 # if OPENSSL_API_COMPAT < 0x10100000L
 #  define OpenSSLDie(f,l,a) OPENSSL_die((a),(f),(l))
 # endif
-void OPENSSL_die(const char *assertion, const char *file, int line);
 # define OPENSSL_assert(e) \
     (void)((e) ? 0 : (OPENSSL_die("assertion failed: " #e, OPENSSL_FILE, OPENSSL_LINE), 1))
 

include/openssl/e_os2.h

@@ -293,6 +293,14 @@ typedef unsigned __int64 uint64_t;
 #  define ossl_inline inline
 # endif
 
+# if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
+#  define ossl_noreturn __attribute__((noreturn))
+# elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L
+#  define ossl_noreturn _Noreturn
+# else
+#  define ossl_noreturn
+# endif
+
 #ifdef  __cplusplus
 }
 #endif