Duplicate Safari

Show Package Contents

Double Click "Contents"

Double Click "Info.plist" to open it with property List Editor

Make a new top-level node called "LSEnvironment"

Set its type to "Dictionary"

Make a new child node called "DYLD_FRAMWORK_PATH"

Set its type to String and its value to whatever run-safari says it should be (/Users/jmelloy/builds)

http://www.visualdistortion.org/misc/safari_wk.png

Presumably that's DYLD_FRAMEWORK_PATH, with an E.