Merge branch 'js/run-command-updates'

* js/run-command-updates:
  api-run-command.txt: describe error behavior of run_command functions
  run-command.c: squelch a "use before assignment" warning
  receive-pack: remove unnecessary run_status report
  run_command: report failure to execute the program, but optionally don't
  run_command: encode deadly signal number in the return value
  run_command: report system call errors instead of returning error codes
  run_command: return exit code as positive value
  MinGW: simplify waitpid() emulation macros

git.c

@@ -416,13 +416,9 @@ 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, 0);
-	if (status != -ERR_RUN_COMMAND_EXEC) {
-		if (IS_RUN_COMMAND_ERR(status))
-			die("unable to run '%s'", argv[0]);
-		exit(-status);
-	}
-	errno = ENOENT; /* as if we called execvp */
+	status = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
+	if (status >= 0 || errno != ENOENT)
+		exit(status);
 
 	argv[0] = tmp;