pci_handler: Add pci_handler

Taken most of the logic from phoshpor-ipmi-flash:
https://github.com/openbmc/phosphor-ipmi-flash/blob/master/tools/io.cpp

Tested: Unit Test + Tested this on a real machine

Signed-off-by: Brandon Kim <brandonkim@google.com>
Change-Id: I546d1dff8764e31c9f2fa6c7465ba23a24f6fdea
diff --git a/meson.build b/meson.build
index 2366091..85d7272 100644
--- a/meson.build
+++ b/meson.build
@@ -9,7 +9,13 @@
     'werror=true',
   ])
 
+root_inc = include_directories('.')
+bios_bmc_smm_error_logger_inc = include_directories('include')
+
 subdir('src')
+if not get_option('tests').disabled()
+  subdir('test')
+endif
 
 # installation of systemd service files
 subdir('service_files')