Fix build failure with "make macports"
Fix build failure with "make macports"

The issue is that on Linux DLLs need not have all symbols resolved.
There is an option to do this on OSX, which I added to the macports
makefile rule.

Fixes issue #191

mongrel2/mongrel2,cpick/mongrel2,chickenkiller/mongrel2,musl/mongrel2,fanout/mongrel2,mongrel2/mongrel2,mongrel2/mongrel2,jablkopp/mongrel2,cpick/mongrel2,pjkundert/mongrel2,cpick/mongrel2,jiffyjeff/mongrel2,aidenkeating/mongrel2,pjkundert/mongrel2,jasom/mongrel2,jablkopp/mongrel2,chickenkiller/mongrel2,cpick/mongrel2,jiffyjeff/mongrel2,krakensden/mongrel2,musl/mongrel2,krakensden/mongrel2,aidenkeating/mongrel2,chickenkiller/mongrel2,fanout/mongrel2,elo80ka/mongrel2,jdesgats/mongrel2,elo80ka/mongrel2,cpick/mongrel2,fanout/mongrel2,cpick/mongrel2,chickenkiller/mongrel2,elo80ka/mongrel2,jasom/mongrel2,aidenkeating/mongrel2,jiffyjeff/mongrel2,krakensden/mongrel2,elo80ka/mongrel2,apjanke/mongrel2,jdesgats/mongrel2,jablkopp/mongrel2,apjanke/mongrel2,musl/mongrel2,jdesgats/mongrel2,jiffyjeff/mongrel2,pjkundert/mongrel2,chickenkiller/mongrel2,jablkopp/mongrel2,apjanke/mongrel2,jasom/mongrel2,krakensden/mongrel2,mongrel2/mongrel2,elo80ka/mongrel2,fanout/mongrel2,aidenkeating/mongrel2,jiffyjeff/mongrel2,pjkundert/mongrel2,aidenkeating/mongrel2,aidenkeating/mongrel2,krakensden/mongrel2,pjkundert/mongrel2,jdesgats/mongrel2,fanout/mongrel2,mongrel2/mongrel2,chickenkiller/mongrel2,jdesgats/mongrel2,apjanke/mongrel2,jasom/mongrel2,apjanke/mongrel2,jablkopp/mongrel2,musl/mongrel2,musl/mongrel2,mongrel2/mongrel2,jasom/mongrel2