Re: What's cooking in git.git (Nov 2012, #03; Tue, 13)

From: Jeff King <peff@peff.net>
Date: Nov 15, 2012, 00:16 UTC
Message-ID: <20121115001635.GA17370@sigill.intra.peff.net>
In-Reply-To: <50A40978.2060504@web.de>

On Wed, Nov 14, 2012 at 10:13:28PM +0100, Torsten Bögershausen wrote:

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> >>>> * ml/cygwin-mingw-headers (2012-11-12) 1 commit
> >>>>  - Update cygwin.c for new mingw-64 win32 api headers
> >>>>
> >>>>  Make git work on newer cygwin.
> >>>>
> >>>>  Will merge to 'next'.

I'm cc-ing Junio in case he missed the discussion; my original plan had been to move this topic right to 'next' to get exposure from other cygwin people. But it seems we have already got that, and it might need re-rolling, so it probably makes sense to hold back until the discussion reaches a conclusion.

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> There are a couple of things which we may want consider:
> a) the name V15_MINGW_HEADERS:
>   It indicates that this is true for Version 1.5 (of what?)
>   If I assume Cygwin version 1.5 , then this name is confusing.
>   Even cygwin versions like 1.7.7 use the same (or similar) include files as 1.5
>   A better name could be CYGWIN_USE_MINGW_HEADERS (or the like) and to revert the logic.

Regardless of flipping the logic, I agree that having CYGWIN in the name makes a lot of sense.

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> b) Autodetection:
>   (Just loud thinking), running 
> $grep mingw /usr/include/w32api/winsock2.h
>  * This file is part of the mingw-w64 runtime package.
> #include <_mingw_unicode.h>
> 
> on cygwin 1.7.17 indicates that we can use grep in the Makefile to
> autodetect the "mingw headers"

Hmm. Can we rely on the /usr/include bit, though?

I assume a test-compile would be sufficient, but currently we do not do anything more magic than "uname" in the Makefile itself to determine defaults. Maybe it would be better to do the detection in the configure script? And then eventually flip the default in the Makefile once sufficient time has passed for most people to want the new format (which would not be necessary for people using autoconf, but would help people who do not).

-Peff