likwid: Fix build (#7244)

likwid uses the current directory when building the paths to its
internal libraries. Spack overwrites PWD, causing likwid to not find
hwloc.h.

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

@@ -24,6 +24,7 @@
 ##############################################################################
 from spack import *
 import glob
+import os
 
 
 class Likwid(Package):
@@ -105,5 +106,6 @@ def install(self, spec, prefix):
                             spec['lua'].prefix.bin),
                         'config.mk')
 
+        env['PWD'] = os.getcwd()
         make()
         make('install')