Reworking of lapack_shared_libs and similar properties (#1682)

* Turned <provider>_libs into an iterable

Modifications :
- added class LibraryList + unit tests
- added convenience functions `find_libraries` and `dedupe`
- modifed non Intel blas/lapack providers
- modified packages using blas_shared_libs and similar functions

* atlas : added pthread variant

* intel packages : added lapack_libs and blas_libs

* find_library_path : removed unused function

* PR review : fixed last issues

* LibraryList : added test on __add__ return type

* LibraryList : added __radd__ fixed unit tests

fix : failing unit tests due to missing `self`

* cp2k and dependecies : fixed blas-lapack related statements in package.py

var/spack/repos/builtin/packages/trilinos/package.py

@@ -132,6 +132,8 @@ def install(self, spec, prefix):
 
         mpi_bin = spec['mpi'].prefix.bin
         # Note: -DXYZ_LIBRARY_NAMES= needs semicolon separated list of names
+        blas = spec['blas'].blas_libs
+        lapack = spec['lapack'].lapack_libs
         options.extend([
             '-DTrilinos_ENABLE_ALL_PACKAGES:BOOL=ON',
             '-DTrilinos_ENABLE_ALL_OPTIONAL_PACKAGES:BOOL=ON',
@@ -145,12 +147,10 @@ def install(self, spec, prefix):
             '-DTPL_ENABLE_MPI:BOOL=ON',
             '-DMPI_BASE_DIR:PATH=%s' % spec['mpi'].prefix,
             '-DTPL_ENABLE_BLAS=ON',
-            '-DBLAS_LIBRARY_NAMES=%s' % to_lib_name(
-                spec['blas'].blas_shared_lib),
+            '-DBLAS_LIBRARY_NAMES=%s' % ';'.join(blas.names),
             '-DBLAS_LIBRARY_DIRS=%s' % spec['blas'].prefix.lib,
             '-DTPL_ENABLE_LAPACK=ON',
-            '-DLAPACK_LIBRARY_NAMES=%s' % to_lib_name(
-                spec['lapack'].lapack_shared_lib),
+            '-DLAPACK_LIBRARY_NAMES=%s' % ';'.join(lapack.names),
             '-DLAPACK_LIBRARY_DIRS=%s' % spec['lapack'].prefix.lib,
             '-DTrilinos_ENABLE_EXPLICIT_INSTANTIATION:BOOL=ON',
             '-DTrilinos_ENABLE_CXX11:BOOL=ON',