[FFmpeg-devel] [PATCH] configure: Use libgcrypt-config if available

[James Almer]

On 1/8/2016 6:39 PM, Ricardo Constantino wrote:
> On 8 January 2016 at 20:40, James Almer <jamrial at gmail.com> wrote:
> 
>> Shouldn't this also check libgcrypt-config --cflags? Assuming
>> the library is in an unusual path, the above will look for
>> the header in whatever include path configure was using by
>> then and either fail or include the wrong headers.
> 
> 
> The issue was -lgpg-error wasn't being included, not that the libs were in
> a unusual path.

But what if they are? The current check will look at whatever include path
configure was using at that point. If gcrypt was installed elsewhere,
libgrypt-config --libs will give the correct library path but the check will
nonetheless use an incorrect include path, which as i said may contain
incorrect gcrypt headers (old version, host gcrypt instead of target, etc),
or no headers at all.

You need to use the output of libgrypt-config --cflags for the check, then add
it to cflags, like all the pkg-config checks do.