[polari] build: Include prefix in libdir & co.

[Gitlab Administrative User <gitlab src gnome org>]

commit 228d81a2ccdd6f955595d0bec09c3e3a00b11e4c
Author: Jan Tojnar <jtojnar gmail com>
Date:   Thu Nov 9 13:59:17 2017 +0100

    build: Include prefix in libdir & co.
    
    Previously, when absolute `libdir` path was needed, it was joined
    with `prefix` on the spot. This meant the libraries used relative
    `install_dir` when `libdir` option was not passed. This in turn
    caused issues for NixOS’s patched Meson which needs absolute paths
    to be able to use them in generated GIR files.
    
    This commit initializes `bindir`, `libdir`, and `datadir` with
    `prefix` in the top-level meson.build.

 data/meson.build | 2 +-
 meson.build      | 6 +++---
 src/meson.build  | 4 ++--
 3 files changed, 6 insertions(+), 6 deletions(-)
---
diff --git a/data/meson.build b/data/meson.build
index 5d3dc32..bfff80b 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -20,7 +20,7 @@ if (desktop_file_validate.found())
 endif
 
 service_conf = configuration_data()
-service_conf.set('bindir', join_paths(prefix, bindir))
+service_conf.set('bindir', bindir)
 
 services = [
   'org.freedesktop.Telepathy.Client.Polari.service',
diff --git a/meson.build b/meson.build
index e66afd6..a7edb51 100644
--- a/meson.build
+++ b/meson.build
@@ -11,9 +11,9 @@ i18n = import('i18n')
 
 prefix = get_option('prefix')
 
-bindir = get_option('bindir')
-libdir = get_option('libdir')
-datadir = get_option('datadir')
+bindir = join_paths(prefix, get_option('bindir'))
+libdir = join_paths(prefix, get_option('libdir'))
+datadir = join_paths(prefix, get_option('datadir'))
 
 pkglibdir = join_paths(libdir, meson.project_name())
 pkgdatadir = join_paths(datadir, meson.project_name())
diff --git a/src/meson.build b/src/meson.build
index f59642d..a030113 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -73,8 +73,8 @@ exeargs = [
   '-DPACKAGE_NAME="polari"',
   '-DPACKAGE_VERSION="@0@"'.format(meson.project_version()),
   '-DPREFIX="@0@"'.format(prefix),
-  '-DLIBDIR="@0@"'.format(join_paths(prefix, libdir)),
-  '-DPKGLIBDIR="@0@"'.format(join_paths(prefix, pkglibdir))
+  '-DLIBDIR="@0@"'.format(libdir),
+  '-DPKGLIBDIR="@0@"'.format(pkglibdir)
 ]
 polari = executable('polari', ['polari.c', src_resources, data_resources],
   dependencies: [gio, girepository, gjs],