I've been having trouble getting PVM 3.4.5 to install under MacPorts on Leopard. The conf/DARWIN.def
configuration file defines the FAKEXDRFLOAT
preprocessor symbol; it may be needed for OS X 10.4, but it causes a compiler error w. GCC 4.0.1 under 10.5:
../../src/pmsg.c:785: error: static declaration of 'xdr_float' follows non-static declaration.
$ sudo port install pvm +darwin_8