- remove the old LGPL license headers from all files in Spack
- add SPDX headers to all files
- core and most packages are (Apache-2.0 OR MIT)
- a very small number of remaining packages are LGPL-2.1-only
* bison: Add missing build dependencies
bison also depends on cmp, which is currently not available in Spack.
* help2man: Add missing build dependency
* m4: Fix build with newer versions of glibc
* openssl: Add missing build dependency
openssl's configure script is actually a Perl script.
* texinfo: Add missing perl dependency
* diffutils: New package
* findutils: Fix build with newer versions of glibc
* mvapich2, mpich: Add missing findutils dependency
m4 exited immediately (causing the nettle build to fail).
```
(alice)[11:09:46]spack>>/Users/hartzell/tmp/spack-mac/spack/opt/spack/darwin-highsierra-x86_64/clang-9.1.0-apple/m4-1.4.18-caxsf7l5yd7qbq2bown6bzi5el3ltfwf/bin/m4
Abort trap: 6
(alice)[11:10:18]spack>>fg
```
Tracked down a fix via the Homebrew recipe. I'll send a note to the
`bug-m4@gnu.org` list to ensure that upstream knows about it.
* AutotoolsPackage: added configure_directory to permit build out of source. The configure script executable is now invoked with an absolute path. Modified a few packages accordingly.
* build_systems: functions returning directories are now properties
* build_systems: fixed issues with tcl and tk
* AutotoolsPackage: reworked recipe for autoreconf
