[gobject-introspection/wip/smcv/search-paths: 3/6] build: Leave gir_dir_prefix unexpanded

[Simon McVittie <smcv src gnome org>]

commit a06edfbb41f414ce88fa4f75cb6a17e8fe114eee
Author: Simon McVittie <smcv debian org>
Date:   Wed Feb 10 11:47:42 2021 +0000

    build: Leave gir_dir_prefix unexpanded
    
    This will let us append it to relative paths inside giscanner.
    
    Signed-off-by: Simon McVittie <smcv debian org>

 meson.build | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)
---
diff --git a/meson.build b/meson.build
index e81623e5..629abba3 100644
--- a/meson.build
+++ b/meson.build
@@ -91,14 +91,13 @@ config.set('GI_MICRO_VERSION', gi_versions[2])
 
 config.set_quoted('GIR_SUFFIX', 'gir-1.0')
 gir_dir_prefix = get_option('gir_dir_prefix')
-if gir_dir_prefix == ''
-    gir_dir_prefix = join_paths(get_option('prefix'), get_option('datadir'))
+if gir_dir_prefix == '' or gir_dir_prefix == get_option('datadir')
+    gir_dir_prefix = get_option('datadir')
     gir_dir_pc_prefix = '${datadir}'
 else
-    gir_dir_prefix = join_paths(get_option('prefix'), gir_dir_prefix)
     gir_dir_pc_prefix = join_paths('${prefix}', gir_dir_prefix)
 endif
-girdir = join_paths(gir_dir_prefix, 'gir-1.0')
+girdir = join_paths(get_option('prefix'), gir_dir_prefix, 'gir-1.0')
 config.set_quoted('GIR_DIR', girdir)
 config.set_quoted('GOBJECT_INTROSPECTION_LIBDIR', join_paths(get_option('prefix'), get_option('libdir')))