Re: Stop mktables from needlessly re-running when using dmake on Win32

Re: Stop mktables from needlessly re-running when using dmake on Win32
Message-ID: <9b18b311050307172455a5816e@mail.gmail.com>

Change 24004 stopped mktables from needlessly re-running when using
dmake on Win32, but it can still happen when using nmake because it
doesn't support the .UPDATEALL attribute that was used to fix dmake.
e.g. Build perl, touch a core header file, then rebuild -- mktables
re-runs when it didn't need to, and 7 times over at that!  This change
alleviates the pain by making mktables exit quickly in such cases.

p4raw-id: //depot/perl@24056