Fix Libs/SharedLibraryIxes.py
Fix Libs/SharedLibraryIxes.py

Accommodate the renaming of libfoo shared libraries to cygfoo under
Cygwin.

timj/scons,timj/scons,andrewyoung1991/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons