Module.globalPaths is still set to a read-only copy of the global
include paths pulled off of the NODE_PATH environment variable.
It's important to be able to inspect this, but modifying it no longer
has any effect.
This path adds an additional cache to the module system for caching the
location of previously required modules. Since it is embedded in the
loop that iterates over all require.paths, this patch also handles the
case where require.paths is being modified.
The patch also cleans up some code around it.
See: https://groups.google.com/forum/#!topic/nodejs-dev/QGGlrvLDHVs
isaacs
Ryan Dahl
Felix Geisendörfer