build: use allowed over enabled

Meson feature options are typically in a tri-state of enabled, disabled,
or auto.  The enabled and disabled functions on an option (from
`get_option`) no longer return true for auto features.  Instead, the
expectation is to use `allowed()` which is true for both enabled and auto.

Switch all uses of `enabled` to `allowed`.

Change-Id: I37fcb391dcb215a86a60c26f7512f6ccb8312dc4
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/test/meson.build b/test/meson.build
index ca71994..92225b4 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -7,7 +7,7 @@
             gtest,
         ],
         link_args: dynamic_linker,
-        build_rpath: get_option('oe-sdk').enabled() ? rpath : '',
+        build_rpath: get_option('oe-sdk').allowed() ? rpath : '',
         implicit_include_directories: false,
         include_directories: '..',
     )
@@ -21,7 +21,7 @@
             gtest,
         ],
         link_args: dynamic_linker,
-        build_rpath: get_option('oe-sdk').enabled() ? rpath : '',
+        build_rpath: get_option('oe-sdk').allowed() ? rpath : '',
         implicit_include_directories: false,
         include_directories: '..',
     )