Trying to build a python egg
Make it possible to apply patches multiple time

By simply adding the -N option: skip reverse patches.
Patching of external projects can be applied mutliple times

Patching is applied through a child process that never fails. Not very safe, but the command can be
called mutliple times without getting a failure.
Patch scripts are now bash scripts
rpath.cmake needs LIBRARY_INSTALL_PATH

It needs to be included after InstallPaths. Or we could redefine all these includes with macros
taking appropriate arguments. Current implementation is not very elegant.
Rpath modified via a function

This makes it easier to add rpath from Trilinos installation directory.
TBB libraries explictly found via rpath
Adding step to patch rpath of TBBs in Trilinos
Fixing RPaths after install

Trying a different approach that should be more robust.
The rpaths are fixed at the end of the install process.
This is done by adding a post-install script.
Because CMake can be awkward, a post-install script is an install script executed in the last
included subdirectory. This subdirectory is created explicitly.
Fake post-install subdir needs explicit binary dir
Seems rpaths are not relative
TBB were not being changed to @rpath/libtbb