Integrate openpower-libhei with openpower-hw-diags

Pull down openpower-libhei as a subproject and build the isolator
support into openpower-hw-diags.

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: I6eeacc802363fec6f0f113e75eb268a8c1774b7c
diff --git a/src/meson.build b/src/meson.build
index ae1b040..407f66f 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -1 +1,9 @@
-executable('openpower-hw-diags', 'main.cpp', install : true)
+# If libhei is not provided by the system then build using the subproject
+libhei_dep = dependency('libhei', fallback : ['libhei', 'libhei_dep'])
+
+# create openpower-hw-diags application
+executable('openpower-hw-diags',
+           'main.cpp',
+           'user_interface.cpp',
+           dependencies : libhei_dep,
+           install : true)