where is the libpq++ ??

hello,

I 've upgrade to 7.3.1 but when i try to add libpq++ interface, i don't 
find it ??
in my interfaces dir there are:

drwxrwxrwx    2 70       70           4096 déc 22 05:32 cli/
drwxrwxrwx    6 70       70           4096 déc 22 05:32 ecpg/
drwxrwxrwx    4 70       70           4096 déc 22 05:33 jdbc/
drwxrwxrwx    2 70       70           4096 déc 22 05:34 libpgtcl/
drwxrwxrwx    3 70       70           4096 jan 23 09:55 libpq/
-rw-r--r--    1 70       70            900 aoû 30 15:06 Makefile
drwxrwxrwx    3 70       70           4096 déc 22 05:34 python/

how to compile libpq++ interface ?
thank.