[libgee/meson] Meson: Fix .pc file generation variables

[Daniel Espinosa Ortiz <despinosa src gnome org>]

commit f71108981f6f45a58cb462a8ece5eef26725c393
Author: Daniel Espinosa <daniel espinosa pwmc mx>
Date:   Mon May 15 10:35:04 2017 -0500

    Meson: Fix .pc file generation variables

 meson.build |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/meson.build b/meson.build
index 57e257f..51d7a08 100644
--- a/meson.build
+++ b/meson.build
@@ -13,9 +13,11 @@ PROJECT_VERSION = '0.20.0'
 
 conf = configuration_data()
 conf.set('prefix', get_option('prefix'))
-conf.set('exec_prefix', get_option('prefix'))
-conf.set('libdir', join_paths (get_option ('prefix'),get_option ('libdir')))
-conf.set('includedir', get_option ('includedir'))
+conf.set('exec_prefix', '${prefix}')
+conf.set('libdir', join_paths ('${prefix}',get_option ('libdir')))
+conf.set('includedir', join_paths ('${prefix}',get_option ('includedir')))
+conf.set('datarootdir', join_paths ('${prefix}','share'))
+conf.set('datadir', '${datarootdir}')
 conf.set('VALADEPS', VALADEPS)
 conf.set('PCDEPS', PCDEPS)
 conf.set('VERSION', PROJECT_VERSION)