[libadwaita] Revert "Remove usage of meson.source/build_root()"

[Alexander Mikhaylenko <alexm src gnome org>]

commit 4ca44b2b080aaff98dca78133314c88a7dbb3d6f
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Nov 2 23:23:22 2021 +0000

    Revert "Remove usage of meson.source/build_root()"
    
    This reverts commit 847fac220653fa38b88980474452caff0847d900

 meson.build     | 2 +-
 src/meson.build | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/meson.build b/meson.build
index be1ec60e..f8bee36b 100644
--- a/meson.build
+++ b/meson.build
@@ -28,7 +28,7 @@ libversion = '@0@.@1@.@2@'.format(soversion, current, revision)
 add_project_arguments([
   '-DHAVE_CONFIG_H',
   '-DADWAITA_COMPILATION',
-  '-I' + meson.project_build_root(),
+  '-I' + meson.build_root(),
 ], language: 'c')
 
 root_inc = include_directories('.')
diff --git a/src/meson.build b/src/meson.build
index 8ff2e9d7..addbd3fa 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -241,7 +241,7 @@ libadwaita_link_args = []
 libadwaita_symbols_file = 'libadwaita.syms'
 
 # Check linker flags
-ld_version_script_arg = '-Wl,--version-script,@0@/@1@'.format(meson.project_source_root(),
+ld_version_script_arg = '-Wl,--version-script,@0@/@1@'.format(meson.source_root(),
                                                               libadwaita_symbols_file)
 if cc.links('int main() { return 0; }', args : ld_version_script_arg, name : 'ld_supports_version_script')
   libadwaita_link_args += [ld_version_script_arg]