build: meson: Remove polkit_dir option

meson is able to get variables defined in pkg-config files such as
directory paths. PolicyKit defines in its pkg-config file the path to
the directory where `policy` files are present.

This removes the `polkit_dir` option to ease the move to start using
those variables. The `polkit` variable has also been converted to
boolean.

Fedora spec script has also been updated accordingly.

contrib/fedora/rpm/NetworkManager.spec

@@ -530,7 +530,7 @@ by nm-connection-editor and nm-applet in a non-graphical environment.
 	-Dovs=false \
 %endif
 	-Dselinux=true \
-	-Dpolkit=yes  \
+	-Dpolkit=true  \
 	-Dpolkit_agent=true \
 	-Dmodify_system=true \
 	-Dconcheck=true \

meson.build

@@ -462,9 +462,7 @@ endif
 config_h.set10('WITH_JSON_VALIDATION', enable_json_validation)
 
 # polkit
-polkit = get_option('polkit')
-enable_polkit = (polkit != 'no')
-
+enable_polkit = get_option('polkit')
 if enable_polkit
   polkit_dir = get_option('polkit_dir')
   if polkit_dir == ''

meson_options.txt

@@ -16,7 +16,7 @@ option('dist_version', type: 'string', value: '', description: 'Define the NM\'s
 option('session_tracking_consolekit', type: 'boolean', value: true, description: 'Support consolekit session tracking')
 option('session_tracking', type: 'combo', choices: ['systemd', 'elogind', 'no'], value: 'systemd', description: 'Compatibility option to choose one session tracking module')
 option('suspend_resume', type: 'combo', choices: ['upower', 'systemd', 'elogind', 'consolekit', 'auto'], value: 'auto', description: 'Build NetworkManager with specific suspend/resume support')
-option('polkit', type: 'combo', choices: ['yes', 'no', 'disabled'], value: 'yes', description: 'set default value for auth-polkit configuration option. This value can be overwritten by NM configuration. \'disabled\' compiles NM without any support')
+option('polkit', type: 'boolean', value: true, description: 'User auth-polkit configuration option.')
 option('modify_system', type: 'boolean', value: false, description: 'Allow users to modify system connections')
 option('polkit_agent', type: 'boolean', value: false, description: 'enable polkit agent for clients')
 option('selinux', type: 'boolean', value: true, description: 'Build with SELinux')