Revert "build: use allowed over enabled"

The meson options used here are dependency checks which should be
handled by the disabler flow.

This reverts commit dabaffecf4eb345e71ee942a9035ddaa5e0eb8ac.

Change-Id: Ia81d168d975efc2c97fd0fefcfee624f2571e1e8
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/example/meson.build b/example/meson.build
index 4911a67..c7ebf61 100644
--- a/example/meson.build
+++ b/example/meson.build
@@ -14,7 +14,7 @@
 endif
 
 assert(
-    not get_option('examples').allowed() or has_asio,
+    not get_option('examples').enabled() or has_asio,
     'Boost is required when examples are enabled'
 )
 
diff --git a/test/meson.build b/test/meson.build
index b72bff0..2efdfeb 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -13,7 +13,7 @@
         gmock_dep = gtest_proj.dependency('gmock')
     else
         assert(
-            not get_option('tests').allowed(),
+            not get_option('tests').enabled(),
             'Googletest is required if tests are enabled'
         )
     endif
@@ -55,7 +55,7 @@
 endforeach
 
 assert(
-    not get_option('tests').allowed() or boost_dep.found(),
+    not get_option('tests').enabled() or boost_dep.found(),
     'Boost is required when tests are enabled'
 )