[Clamav-devel] Problem compiling with libxml2 and Xcode 9

[Mark Allan]

Hi all,

I just updated Xcode (Apple's developer tools for macOS) to version 9 and I'm no longer able to compile ClamAV 0.99.2 with libxml2 support.

Here's the relevant output from the configure script:

> ...
> checking for libxml2 installation... /usr
> checking xml2-config version... 2.9.4
> checking for xmlreader.h in /usr... found
> checking for xmlTextReaderRead in -lxml2... no
> configure: ****** libxml2 support unavailable
> ...
> configure: Summary of engine detection features
>               bzip2       : ok
>               zlib        : /usr
>               unrar       : yes
>               pcre        : /usr/local/clamXav
>               libxml2     : no
>               yara        : yes

I'm aware that things tend to break when updating Xcode, so I did this test in a virtual machine, which means I can say with certainty that the devtools are the only things to have changed. If I revert to the snapshot with Xcode 8.3, the configure script finds everything it needs to within /usr:

> ...
> checking for libxml2 installation... /usr
> checking xml2-config version... 2.9.4
> checking for xmlreader.h in /usr... found
> checking for xmlTextReaderRead in -lxml2... yes
> configure: Compiling and linking with libxml2 from /usr
> ...
> configure: Summary of engine detection features
>               bzip2       : ok
>               zlib        : /usr
>               unrar       : yes
>               pcre        : /usr/local/clamXav
>               libxml2     : yes, from /usr
>               yara        : yes

If I update again (or go back to the snapshot with Xcode 9) it fails.

I've compared the checksums of the libraries in /usr/lib/libxml2.* and they're identical before and after the upgrade. Similarly, diffing the contents of /usr/include/libxml2/libxml shows they're exactly the same too, so I'm not quite sure what's going on.

Can anyone help shed some light on the matter please?

Many thanks
Mark