Resolving `ZLIB_1.2.3.3' not found

After installing some libraries for php I got something broken.

I couldn't open synaptic, pidgin, and other programs.

They all said:
/usr/lib/libz.so.1: version `ZLIB_1.2.3.3' not found (required by /usr/lib/i386-linux-gnu/libxml2.so.2)

despite the content of the folder looks like this

$ ls -l /usr/lib/libz*
lrwxrwxrwx 1 root root     18 2010-05-13 21:30 /usr/lib/libzephyr.so.3 -> libzephyr.so.3.0.0
-rw-r--r-- 1 root root  39180 2008-10-06 18:55 /usr/lib/libzephyr.so.3.0.0
lrwxrwxrwx 1 root root     23 2011-03-20 19:26 /usr/lib/libzrtpcpp-1.3.so.0 -> libzrtpcpp-1.3.so.0.0.0
-rw-r--r-- 1 root root 155724 2008-07-03 18:12 /usr/lib/libzrtpcpp-1.3.so.0.0.0
lrwxrwxrwx 1 root root     15 2010-05-13 21:30 /usr/lib/libz.so.1 -> libz.so.1.2.3.3
-rw-r--r-- 1 root root  81012 2013-06-04 13:35 /usr/lib/libz.so.1.2.3.3


Luckily the solution was very simple

# sudo apt-get install zlib1g

I found the answer here http://www.istitutomajorana.it/forum/Thread-RISOLTO-Trovare-librerie

Thanks a million!