On 05/21/2017 04:54 PM, clipka wrote:
> I think what we should do, in a nutshell, is the following:
> 
> - Inform the users that they may need the pkg-config package (if they
> want to use OpenEXR).
> 
> - In the absence of pkg-config, or if pkg-config fails to come up with
> any useful information, make a reasonable attempt to determine the
> OpenEXR version in another manner, and make a reasonable guess at the
> additional compiler and linker flags required (if any).
> 
> - Make sure our configure script contains a test to verify that the
> OpenEXR library can be linked using the chosen compiler and linker flags.
> 
> 
> I also wonder whether we should make our handling of libraries more
> consistent, and make use of pkg-config for other libraries as well where
> possible.
> 
> As a side note, I noticed that the automake tools apparently provide
> dedicated macros to make use of pkg-config; those might be worth a
> closer look, even if in the end we decide against them (their use seems
> to be controversial due to some known issues, so if we decide to use
> them nonetheless, we should clearly document those issues).
> 

Thanks for the guidance. I'll work this direction.

I think we should look to use pkg-config only where the library itself 
seems to support it with the necessary *.pc information. Though, hacking 
our own *.pc files where they are missing or inaccurate would be a 
possible path too I guess...

Yes, a test compile and test link with whatever flags we determine to 
use makes good sense.

FYI. It turns out pkg-config does provide the flags necessary to fix the 
--enable-static link issue with libtiff I mentioned somewhere in this 
thread. We are always using just

-ltiff

which "pkg-config --libs libtiff-4" returns too. If we ask for the 
static flags with: "pkg-config --libs --static libtiff-4" we get:

-ltiff -llzma -ljbig -ljpeg -lz -lm

where -llzma and -ljbig are unique to what we end up with today in the 
Makefiles and necessary for the static link to work. So, we have already 
one issue that using pkg-config should fix for many *nix based users.

I also got my hands on an old book on autoconf & automake yesterday, 
which I'll continue to look through today. I know a smidgen now about M4 
to the envy of millions. ;-)

Bill P.

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