meson: use current_source_dir instead of source_root
Use source_root breaks the build when used as a subproject.
@@ -196,7 +196,7 @@ git = find_program('git', required: false)
if git.found()
all_files = run_command(
git,
- ['--git-dir=@0@/.git'.format(meson.source_root()),
+ ['--git-dir=@0@/.git'.format(meson.current_source_dir()),
'ls-files',
':/*.[ch]'])
all_files = files(all_files.stdout().split())
