Add a fatal error handler.

src/vmod_gcrypt.c

@@ -128,12 +128,23 @@ gcrypt_logger(void *priv, int level, const char *fmt, va_list args)
 		lvl = "DEBUG";
 		break;
 	default:
-		VSL(SLT_Error, 0, "Unknown gcrypt log level %d", level);
+		VSL(SLT_Error, 0, "Unknown libgcrypt log level %d", level);
 	}
 	VSL(tag, 0, "libgcrypt log message follows (%s):", lvl);
 	VSLv(tag, 0, fmt, args);
 }
 
+static void  __match_proto__(gcry_handler_error_t)
+gcrypt_fatal(void *priv, int err, const char *text)
+{
+	(void) priv;
+	if (text == NULL)
+		text = gpg_strerror(err);
+	VSL(SLT_Error, 0, "libgcrypt fatal error, code=%d (%s), panic follows",
+	    err, text);
+	AZ(text);
+}
+
 int __match_proto__(vmod_event_f)
 event(VRT_CTX, struct vmod_priv *priv, enum vcl_event_e e)
 {
@@ -144,6 +155,7 @@ event(VRT_CTX, struct vmod_priv *priv, enum vcl_event_e e)
 		if (gcrypt_version != NULL)
 			return 0;
 		gcry_set_log_handler(gcrypt_logger, NULL);
+		gcry_set_fatalerror_handler(gcrypt_fatal, NULL);
 		gcrypt_version = gcry_check_version(MIN_GCRYPT_VERSION);
 		if (gcrypt_version == NULL) {
 			VSL(SLT_VCL_Error, 0,