Heroku libfaketime buildpack

This is a simple Heroku buildpack to inject libfaketime.

The script will simply download the library, compile it and place it inside the /app/vendor/libfaketime directory. It will also set the following variables through profile.d:

FAKETIME_NO_CACHE=1
LD_PRELOAD=/app/vendor/libfaketime/libfaketime.so.1

In order to specify new time, provide FAKETIME variable, i.e.:

FAKETIME=+1d