[cairo] Making configure error message more clear

[Arjen Nienhuis]

On Fri, Mar 26, 2010 at 4:37 AM, Behdad Esfahbod
<behdad.esfahbod at gmail.com> wrote:
> On 03/25/2010 05:53 PM, Bill Spitzak wrote:
>>
>>>   - If we only use $PREFIX/lib/pkgconfig if PKG_CONFIG_PATH is not
>>> set, then
>>> user setting PKG_CONFIG_PATH to another location will break the build
>>> since
>>> they now have to add $PREFIX/lib/pkgconfig manually.
>>
>> I don't understand what is wrong with this solution. If they are setting
>> it, then they have probably set it correctly, thus it either includes
>> this directory, or that directory is not needed.
>
> For example, my .bash_profile always adds ~/.local/lib/pkg-config to
> PKG_CONFIG_PATH.  Doesn't mean I have set /usr/local/lib/pkg-config in it.
>

Yeah, but then it will keep working. It will only change
PKG_CONFIG_PATH if you don't set it at all. And you apparently know
how to fix it. I didn't even know PKG_CONFIG_PATH existed until I had
to build cairo.