build: Stop detecting features automatically

Auto-detect options add some convenience for platforms where a
particular feature isn't available - systemd on non-Linux OS comes
to mind - but the downside is that it is easy to accidentally build
without a desired feature. We consider the latter much more serious
nowadays, so turn our auto-detect options into regular boolean
options.

https://bugzilla.gnome.org/show_bug.cgi?id=791007

meson.build

@@ -102,39 +102,19 @@ if enable_recorder
 endif
 
 nm_deps = []
-enable_networkmanager = get_option('networkmanager')
-if enable_networkmanager != 'no'
-  want_networkmanager = enable_networkmanager == 'yes'
-
-  nm_deps += dependency('libnm-glib',
-    version: nm_req, required: want_networkmanager
-  )
-  nm_deps += dependency('libnm-util',
-    version: nm_req, required: want_networkmanager
-  )
-  nm_deps += dependency('libnm-gtk',
-    version: nm_req, required: want_networkmanager
-  )
-  nm_deps += dependency('libsecret-1',
-    version: secret_req, required: want_networkmanager
-  )
+if get_option('networkmanager')
+  nm_deps += dependency('libnm-glib', version: nm_req)
+  nm_deps += dependency('libnm-util', version: nm_req)
+  nm_deps += dependency('libnm-gtk', version: nm_req)
+  nm_deps += dependency('libsecret-1', version: secret_req)
 
   have_networkmanager = true
-  foreach dep : nm_deps
-    have_networkmanager = have_networkmanager and dep.found()
-  endforeach
-
-  if not have_networkmanager
-    nm_deps = []
-  endif
 else
   have_networkmanager = false
 endif
 
-enable_systemd = get_option('systemd')
-if enable_systemd != 'no'
-  want_systemd = enable_systemd == 'yes'
-  systemd_dep = dependency('libsystemd', required: want_systemd)
+if get_option('systemd')
+  systemd_dep = dependency('libsystemd')
   have_systemd = systemd_dep.found()
 else
   systemd_dep = []

meson_options.txt

@@ -17,15 +17,13 @@ option('man',
 )
 
 option('networkmanager',
-  type: 'combo',
-  choices: ['yes', 'no', 'auto'],
-  value: 'auto',
+  type: 'boolean',
+  value: true,
   description: 'Enable NetworkManager support'
 )
 
 option('systemd',
-  type: 'combo',
-  choices: ['yes', 'no', 'auto'],
-  value: 'auto',
+  type: 'boolean',
+  value: true,
   description: 'Enable systemd integration'
 )