fixup! mingw: spawned processes need to inherit only standard handles

Let's preserve the correct errno (thanks, t0061!)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

compat/mingw.c

@@ -1793,13 +1793,13 @@ static pid_t mingw_spawnve_fd(const char *cmd, const char **argv, char **deltaen
 		ret = CreateProcessW(*wcmd ? wcmd : NULL, wargs, NULL, NULL,
 				     TRUE, flags, wenvblk, dir ? wdir : NULL,
 				     &si.StartupInfo, &pi);
-		if (ret)
+		if (ret) {
+			errno = err_win_to_posix(GetLastError());
 			warning("failed to restrict file handles (%ld)\n\n%s",
 				err, buf.buf);
+		}
 		strbuf_release(&buf);
-	}
-
-	if (!ret)
+	} else if (!ret)
 		errno = err_win_to_posix(GetLastError());
 
 	if (si.lpAttributeList)