First, Happy New Year 2012. wish the best from this year :-)

I take the source from extra directory.
I've got this error when compiling Linux-PAM on slackware64-current.
pam_unix_passwd.c:57:21: fatal error: rpc/rpc.h: No such file or directory
compilation terminated.
make[3]: *** [pam_unix_passwd.lo] Error 1
make[3]: Leaving directory `/tmp/Linux-PAM-1.1.3/modules/pam_unix'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/tmp/Linux-PAM-1.1.3/modules'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/tmp/Linux-PAM-1.1.3'
make: *** [all] Error 2

Any suggest why this happen? Is there anything that I miss?

because of missing NIS stuff in the new rpc headers you have to add --disable-nis to the configure options and it will build (but obviously PAM will lack NIS support).

if you're experimenting with PAM, I suggest you to have a look at this

http://connie.slackware.com/~vbatts/pam/