[gvfs] build: Properly define giomoduledir and session_bus_services_dir

[Iñigo Martínez <inigomartinez src gnome org>]

commit f3bc7a6e8000488dda6703a3ae65ff72cdb3bd80
Author: Iñigo Martínez <inigomartinez gmail com>
Date:   Mon Mar 19 19:47:25 2018 +0100

    build: Properly define giomoduledir and session_bus_services_dir
    
    Following the recommendations[0], the `giomoduledir` and
    `session_bus_services_dir` use the information from the `pc` files
    where they are defined, gio-2.0.pc and dbus-1.pc. However, these
    variables are relative to some other variable which is set to be
    a directory under prefix, where the user should be able to write.
    
    On the other hand, systemd related paths, `systemduserunitdir`
    and `tmpfilesdir` can not use this approach because they use
    absolute paths, so there is no way to set those paths to
    directories under prefix.
    
    The `gio_module_dir` and `dbus_services_dir` have also been removed
    because they are not necessary anymore.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=794365
    
    [0] https://www.bassi.io/articles/2018/03/15/pkg-config-and-paths/

 meson.build       |   16 ++++------------
 meson_options.txt |    2 --
 2 files changed, 4 insertions(+), 14 deletions(-)
---
diff --git a/meson.build b/meson.build
index 5a0bc5e..9651d88 100644
--- a/meson.build
+++ b/meson.build
@@ -267,19 +267,13 @@ endif
 config_h.set('HAVE_GCRYPT', enable_gcrypt)
 
 # *** Check for dbus service dir ***
-dbus_service_dir = get_option('dbus_service_dir')
-if dbus_service_dir == ''
-  dbus_dep = dependency('dbus-1', required: false)
-  assert(dbus_dep.found(), 'dbus-1 required but not found, please provide a valid D-Bus service dir')
-  dbus_service_dir = dbus_dep.get_pkgconfig_variable('session_bus_services_dir')
-endif
+dbus_dep = dependency('dbus-1')
+dbus_service_dir = dbus_dep.get_pkgconfig_variable('session_bus_services_dir', define_variable: ['datadir', 
gvfs_datadir])
 
 dbus_service_in = files('dbus.service.in')
 
-gio_module_dir = get_option('gio_module_dir')
-if gio_module_dir == ''
-  gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir')
-endif
+# *** Check for gio module dir ***
+gio_module_dir = gio_dep.get_pkgconfig_variable('giomoduledir', define_variable: ['libdir', gvfs_libdir])
 
 # *** Check for systemd options ***
 systemd_user_unit_dir = get_option('systemduserunitdir')
@@ -518,8 +512,6 @@ meson.add_install_script(
 
 output = gvfs_name + ' ' + gvfs_version + ' configuration summary:\n'
 output += '\n'
-output += '  dbus_service_dir: ' + dbus_service_dir + '\n'
-output += '  gio_module_dir: ' + gio_module_dir + '\n'
 output += '  systemduserunitdir: ' + systemd_user_unit_dir + '\n'
 output += '  tmpfilesdir: ' + tmp_files_dir + '\n'
 output += '\n'
diff --git a/meson_options.txt b/meson_options.txt
index 5f5041c..2c116a5 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -1,5 +1,3 @@
-option('dbus_service_dir', type: 'string', value: '', description: 'custom directory for dbus service files')
-option('gio_module_dir', type: 'string', value: '', description: 'custom directory for gio modules')
 option('systemduserunitdir', type: 'string', value: '', description: 'custom directory for systemd user 
units, or \'no\' to disable')
 option('tmpfilesdir', type: 'string', value: '', description: 'custom directory for tmpfiles.d config files, 
or \'no\' to disable')