common: Add a status callback to gnupg_exec_tool_stream.
* common/exectool.h (exec_tool_status_cb_t): New. * common/exectool.c: Include missing exectool.h. (read_and_log_buffer_t): Replace array by pointer. (gnupg_exec_tool_stream): Add args 'status_cb' and 'status_cb_value'. Change all callers to pass NULL for them. Malloc buffer for FDERRSTATE. (read_and_log_stderr): Implement status_fd feature.
- Signed-off-by: Werner Koch <wk@gnupg.org>