Error while compiling on Ubuntu 12.10

[Cristian Marchi]

I recently upgraded to Ubuntu 12.10 and I'm triyng to build GnuCash from 
source again. While doing so I get this error when I run make after a 
successful autogen and configure:

In file included from ../../src/backend/xml/sixtp.h:32:0,
                  from ../../src/backend/xml/io-gncxml-v2.h:39,
                  from assistant-xml-encoding.c:39:
../../src/backend/xml/gnc-xml-helper.h:28:31: fatal error: 
libxml/xmlversion.h: No such file or directory
compilation terminated.
make[4]: *** [assistant-xml-encoding.lo] Errore 1
make[4]: uscita dalla directory 
"/home/cristian/unstable/GNUCASH/src-trunk/src/gnome-utils"
make[3]: *** [all-recursive] Errore 1
make[3]: uscita dalla directory 
"/home/cristian/unstable/GNUCASH/src-trunk/src/gnome-utils"
make[2]: *** [all-recursive] Errore 1
make[2]: uscita dalla directory 
"/home/cristian/unstable/GNUCASH/src-trunk/src"
make[1]: *** [all-recursive] Errore 1
make[1]: uscita dalla directory "/home/cristian/unstable/GNUCASH/src-trunk"
make: *** [all] Errore 2

I searched my system for libxml/xmlversion.h and I've found it in 
/usr/include/libxml2/libxml/xmlversion.h

Thanks for any help
Cristian