tree-wide: use xsprintf() where applicable

Also add a coccinelle receipt to help with such transitions.

src/basic/log.c

@@ -352,7 +352,7 @@ static int write_to_console(
         highlight = LOG_PRI(level) <= LOG_ERR && show_color;
 
         if (show_location) {
-                snprintf(location, sizeof(location), "(%s:%i) ", file, line);
+                xsprintf(location, "(%s:%i) ", file, line);
                 IOVEC_SET_STRING(iovec[n++], location);
         }
 
@@ -777,7 +777,7 @@ static void log_assert(
                 return;
 
         DISABLE_WARNING_FORMAT_NONLITERAL;
-        snprintf(buffer, sizeof(buffer), format, text, file, line, func);
+        xsprintf(buffer, format, text, file, line, func);
         REENABLE_WARNING;
 
         log_abort_msg = buffer;