x86-power-control: add passthrough option

Add a power and reset button passthrough option
for emulating button behavior by directly controlling
the control output pin.

Change-Id: I50df3e604401b4afd43fa89a0709466bbf01638b
Signed-off-by: Renze Nicolai <renze@rnplus.nl>
diff --git a/meson.build b/meson.build
index 6117245..80eeed6 100644
--- a/meson.build
+++ b/meson.build
@@ -35,6 +35,9 @@
 if get_option('ignore-soft-resets-during-post').allowed()
   cpp_args += '-DIGNORE_SOFT_RESETS_DURING_POST'
 endif
+if get_option('button-passthrough').allowed()
+  cpp_args += '-DUSE_BUTTON_PASSTHROUGH'
+endif
 
 deps = [
   dependency('libgpiodcxx', default_options: ['bindings=cxx']),