protocol.c:217: error: `PF_UNSPEC' undeclared (first use in this function)

Hi,

i tried to compile libesmtp-1.0 on hpux 11.00 with gnome-2.4, but this =
fails
with the following error message:

/usr/local/include/openssl/ssl.h:1320: warning: function declaration =
isn't a prototype
/usr/local/include/openssl/ssl.h:1322: warning: function declaration =
isn't a prototype
protocol.c: In function `do_session':
protocol.c:155: warning: implicit declaration of function `strdup'
protocol.c:155: warning: assignment makes pointer from integer without a =
cast
protocol.c:217: error: `PF_UNSPEC' undeclared (first use in this =
function)
protocol.c:217: error: (Each undeclared identifier is reported only once
protocol.c:217: error: for each function it appears in.)
protocol.c:218: error: `SOCK_STREAM' undeclared (first use in this =
function)
protocol.c:230: warning: implicit declaration of function `socket'
protocol.c:236: warning: implicit declaration of function `connect'
protocol.c: In function `cb_ehlo':
protocol.c:727: warning: implicit declaration of function `strcasecmp'
protocol.c:739: warning: implicit declaration of function `strncasecmp'
make[3]: *** [protocol.lo] Error 1
make[3]: Leaving directory =
`/data/GARNOME/garnome-0.29.1_stable/fifth-toe/libesmtp/work/main.d/libes=

mtp-1.0'
make[2]: *** [all-recursive] Error 1

any help ?