The 'test/Makefile' had the '..' directory in the include path, which caused the 'HYPRE_config.h' file to be included from two different places (in '..' and in 'install'). In the spack autotest, this caused a conflict.
* Check that 'git describe' works in autoconf build
* Updated versioncheck tests to work when 'git describe' fails
* Updated CMake build to work when 'git describe' fails
* Update autotest filters to ignore error messages from 'git describe'
- Fixed improper inclusion of _hypre_utilities.h in user header files
- Added a 'check-headers.sh' regression test that compiles the examples with
options that output header usage, then checks for internal header files
- Moved HYPRE_Init() to 'HYPRE_utilities.h'
