libmpeg2 wont compile

[Christer Solskogen]

cc -pipe -mcpu=pentiumpro -Wall -fomit-frame-pointer -o .libs/sample2
sample2.o -Wl,-rpath -Wl,/usr/local/lib  ../libmpeg2/.libs/libmpeg2.so
../libvo/libvo.a -lSM -lICE -L/usr/X11R6/lib -lX11 -lXext -lXv
-L/usr/local/lib -lSDL-1.1 -Wl,--rpath -Wl,/usr/local/lib
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_create'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_attr_init'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_exit'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_cancel'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_setcanceltype'
/usr/local/lib/libSDL-1.1.so: undefined reference to
`pthread_attr_setdetachstate'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_join'
/usr/local/lib/libSDL-1.1.so: undefined reference to `pthread_cond_timedwait'
*** Error code 1

Stop in /tmp/usr/ports/multimedia/libmpeg2/work/mpeg2dec-0.3.1/doc.
*** Error code 1

Stop in /tmp/usr/ports/multimedia/libmpeg2/work/mpeg2dec-0.3.1.
*** Error code 1

Stop in /usr/ports/multimedia/libmpeg2.
#

sdl-1.2.5_3 is installed.

any suggestions?
FreeBSD 5.1-RELEASE


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Christer Solskogen
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