> I was trying to compile mplayer and xine, but both ./configure scripts
> reported missing pthread libraries.  I've installed the pth package, and I
> added an option to ./configure (--with-extralibdirs=/usr/pkg/lib/) where

You've told the the script where the pthread libraries are ..

> the libpth and libpthread files are, but it still won't register.  I
> figure I'm probably missing something obvious...
> 
> gcc    /tmp/mplayer-conf--1286.c -o /tmp/mplayer-conf--1286.o
> /tmp/mplayer-conf--1286.c:1: pthread.h: No such file or directory

... but not where the header file are.  Try setting a CPPFLAGS
environment variable before running configure.  Something like

	CPPFLAGS=-I/usr/pkg/include configure ...

David S.