Fixed relsymlink to make more sense

based on trailing slash to distinguish whether the symlink argument is
the exact path of the file to create, or a directory to hold the file
whose name will be the basename of the first target path argument.
Fix for depends checker generator with no deps
Common recipe for bundled and runtime dependencies

`make depends/.module.install` generates the skeleton for bundled
dependencies and runtime dependency checks.
Support for symlinked .module.install files
Sanitizing PATH for safe and correct find -execdir