[Swarm-Support] Missing -lpng on OS X build

[Surajit Nundy (student)]

Hello,
       I am trying to build heatbugs on Mac OS X 10.2.5. It fails with 
a set of path
warnings which seem to have been documented before on this list, but 
with one error
(Can't find -lpng) for which I can't seem to find a workaround in 
previous postings. My
DYLD_LIBRARY_PATH contains the path to the libpng directory as 
installed by the
package.  The tail of the error message is:-

/usr/bin/ld: warning -L: directory name 
(/Users/billn/Public/Swarm/swarm/macosx/
swarmx/build/src/defobj) does not exist
/usr/bin/ld: warning -L: directory name 
(/Users/billn/Public/Swarm/swarm/macosx/
swarmx/build/src/collections) does not exist
/usr/bin/ld: warning -L: directory name 
(/Users/billn/Public/Swarm/swarm/macosx/
swarmx/build/src/misc) does not exist
/usr/bin/ld: warning -L: directory name 
(/Users/billn/Public/Swarm/swarm/macosx/
swarmx/build/libobjc) does not exist
/usr/bin/ld: warning -L: directory name 
(/Users/billn/Public/Swarm/libpng-1.2.5/dst/
usr/local/lib) does not exist
/usr/bin/ld: can't locate file for: -lpng
collect2: ld returned 1 exit status
make: *** [heatbugs] Error 1

I would appreciate it if someone could tell me what I need to do to fix 
this.

Thanks,
Surajit Nundy