install on os x is placed in wrong folder

[Yuantai Du]

scons: Building targets ... Install file: "build/ori/ori" as "/usr/local/bin/bin/ori" Install file: "build/oridbg/oridbg" as "/usr/local/bin/bin/oridbg" Install file: "build/orifs/orifs" as "/usr/local/bin/bin/orifs" Install file: "build/orisync/orisync" as "/usr/local/bin/bin/orisync" Install file: "docs/ori.1" as "/usr/local/bin/share/man/man1/ori.1" Install file: "docs/oridbg.1" as "/usr/local/bin/share/man/man1/oridbg.1" Install file: "docs/orifs.1" as "/usr/local/bin/share/man/man1/orifs.1" Install file: "docs/orisync.1" as "/usr/local/bin/share/man/man1/orisync.1" scons: done building targets.

It appears that the PREFIX in SConstruct file is set to /usr/loca/bin/, instead of /usr/local/