ImageMagick on 5.2-R fails with pthread error

[BSDC]

Trying to install ImageMagick on a FreeBSD 5.2-R system, I get:

Making all in utilities
gmake[1]: Entering directory
`/usr/ports/graphics/ImageMagick/work/ImageMagick-5.5.7/utilities'
/bin/sh ../libtool --silent --mode=link cc  -O -pipe -funroll-loops
-DVM_STACK -march=pentium4 -Wall  -L/usr/local/lib -lc_r
-L/usr/X11R6/lib -L/usr/local/lib -L/usr/local/lib -o composite
-L/usr/local/lib -lc_r -L/usr/X11R6/lib -L/usr/local/lib
-L/usr/local/lib composite.o ../magick/libMagick.la  
/usr/local/lib/libjasper.so: warning: tmpnam() possibly used unsafely;
consider using mkstemp()
../magick/.libs/libMagick.so: undefined reference to `pthread_equal'
gmake[1]: *** [composite] Error 1
gmake[1]: Leaving directory
`/usr/ports/graphics/ImageMagick/work/ImageMagick-5.5.7/utilities'
gmake: *** [all-recursive] Error 1
*** Error code 2

Should it be using -lc_r instead of -pthread? Or is that the correct
thing now in 5.x?