dashed externals: kill children on exit

Several git commands are so-called dashed externals, that is commands
executed as a child process of the git wrapper command. If the git
wrapper is killed by a signal, the child process will continue to run.
This is different from internal commands, which always die with the git
wrapper command.

Enable the recently introduced cleanup mechanism for child processes in
order to make dashed externals act more in line with internal commands.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git.c

@@ -495,7 +495,7 @@ static void execv_dashed_external(const char **argv)
 	 * if we fail because the command is not found, it is
 	 * OK to return. Otherwise, we just pass along the status code.
 	 */
-	status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
+	status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE | RUN_CLEAN_ON_EXIT);
 	if (status >= 0 || errno != ENOENT)
 		exit(status);
 

run-command.c

@@ -497,6 +497,7 @@ static void prepare_run_command_v_opt(struct child_process *cmd,
 	cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
 	cmd->silent_exec_failure = opt & RUN_SILENT_EXEC_FAILURE ? 1 : 0;
 	cmd->use_shell = opt & RUN_USING_SHELL ? 1 : 0;
+	cmd->clean_on_exit = opt & RUN_CLEAN_ON_EXIT ? 1 : 0;
 }
 
 int run_command_v_opt(const char **argv, int opt)

run-command.h

@@ -53,6 +53,7 @@ extern int run_hook(const char *index_file, const char *name, ...);
 #define RUN_COMMAND_STDOUT_TO_STDERR 4
 #define RUN_SILENT_EXEC_FAILURE 8
 #define RUN_USING_SHELL 16
+#define RUN_CLEAN_ON_EXIT 32
 int run_command_v_opt(const char **argv, int opt);
 
 /*