[FFmpeg-devel] [PATCH] build: fix make checkheaders in out-of-tree builds

[Hendrik Leppkes]

On Mon, Jan 25, 2016 at 11:01 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
> On Mon, Jan 25, 2016 at 2:34 AM, Andreas Cadhalpun
> <andreas.cadhalpun at googlemail.com> wrote:
>> On 24.01.2016 22:57, Hendrik Leppkes wrote:
>>> While links are in theory a good idea, creating directory links on
>>> windows requires elevated privileges. Don't ask me why, I don't know,
>>> but that makes this unfortunately impractical.
>>> Copying files around between different physical media is not a
>>> solution, but an ugly hack and a build performance regression. See
>>> earlier point about re-opening the review phase of this change to
>>> discuss such "solutions".
>>
>> Oh well, MSVC just doesn't want this to work...
>>
>> Then let's do it the other way around: create a link from the destination
>> path to the source path.
>> If that link can be created, it can be used as relative path and otherwise
>> one can still use the full source path.
>>
>> Attached is a patch implementing this.
>> It should not be possible that this breaks anywhere.
>>
>> Feel free to apply this if it makes MSVC builds work again.
>>
>
> msys doesn't seem to like creating directory symlinks with ln -s, for
> some reason it copies the folder instead, which is of course terribly
> slow.
> Could try to use the windows link creating function, but thats
> probably too much trouble.
>
> If we already have a way to fallback to the "old way", maybe this
> could be put under a OS conditional, ie. exclude msys/cygwin?
>

Looking at it, we even have a handy configure property that identifies
problem systems:
if enabled dos_paths; then....

- Hendrik