[PATCH V2] configure.ac: Fallback to older detection code if pkg-config can't find expat

[Bill Spitzak]

What happens if I don't enable the scanner?

I believe this means it would be impossible to add new protocol 
messages, right?

On 02/03/2015 01:44 PM, Peter Hutterer wrote:
> On Tue, Feb 03, 2015 at 12:32:22PM -0800, Bill Spitzak wrote:
>> It looks like $(LIBS) is added by automake to every link, I can't figure out
>> a way to stop it. Is this correct?
>
> yes. the goal isn't to stop that, the goal is to keep everything that's not
> a global requirement out of $LIBS :)
>
> Cheers,
>     Peter
>
>> On 02/02/2015 10:46 PM, Peter Hutterer wrote:
>>> On Mon, Feb 02, 2015 at 06:33:49PM -0800, Bill Spitzak wrote:
>>>>
>>>>
>>>> On 02/02/2015 03:12 PM, sardemff7+wayland at sardemff7.net wrote:
>>>>> On 2015-02-02 22:29, Bill Spitzak wrote:
>>>>>> This paritally reverts commit a4afd90f9f0c27ed5f3f313b915c260673f8be34.
>>>>>>
>>>>>> On older expat versions (ie the one on Ubuntu 12.04) there is no
>>>>>> pkg-config
>>>>>> file, so fall back to the previous test for the header file when it
>>>>>> fails.
>>>>>> Test is slightly cleaned up from previous one.
>>>>>>
>>>>>> I could not use AC_SEARCH_LIBS as was suggested, as this leaves the
>>>>>> switch
>>>>>> in LIBS, not EXPAT_LIBS, and thus does not match the pkg-config results.
>>>>>
>>>>> Well, you can perfectly do that, especially since AC_CHECK_LIB does not
>>>>> export EXPAT_LIBS either.
>>>>
>>>> I think I may need some expert autotools help. I was basing these changes on
>>>> looking at what got put into the config.h and Makefile. If I used
>>>> AC_SEARCH_LIBS it added "-lexpat" to LIBS. I could make it also add it to
>>>> EXPAT_LIBS but I could not figure out a way to stop it from being added to
>>>> LIBS.
>>>
>>> the usual process is (used to be?):
>>> SAVE_LIBS="$LIBS"
>>> AC_SEARCH_LIBS(....)
>>> EXPAT_LIBS="$LIBS"
>>> LIBS="$SAVE_LIBS"
>>>
>>> so you save the current state and restore it after it got mangled. we do
>>> that for the rdp compositro CPPFLAGS already for example.