`sbang` is not always accessible to users of packages, e.g., if Spack
is installed in someone's home directory and they deploy software
for others. Avoid this by:
1. Always installing the `sbang` script in the `install_tree`
2. Relocating binaries to point to the copy in the `install_tree`
and not the one in the Spack installation.
This PR also:
- ensures that `sbang` is reinstalled if it is modified in Spack
- adds tests
- updates the way `gobject-introspection` patches Makefiles
to support `sbang`
Co-authored-by: Todd Gamblin <tgamblin@llnl.gov>
1c2c30a139