[sysprof] build: use current_build_dir() instead of build_root()

[Christian Hergert <chergert src gnome org>]

commit d6aabaf1ff9fc24c7754feb1dcbb4f4285d4da8b
Author: Christian Hergert <chergert redhat com>
Date:   Fri Aug 21 15:20:04 2020 -0700

    build: use current_build_dir() instead of build_root()
    
    This can help with subprojects.

 meson.build | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/meson.build b/meson.build
index 1060520a..4ddc8ee1 100644
--- a/meson.build
+++ b/meson.build
@@ -84,7 +84,7 @@ has_clockid = cc.has_member('struct perf_event_attr', 'clockid', prefix: '#inclu
 config_h.set('HAVE_PERF_CLOCKID', has_use_clockid and has_clockid)
 
 add_project_arguments([
-  '-I' + meson.build_root(), # config.h
+  '-I' + meson.current_build_dir(), # config.h
 ], language: 'c')
 
 global_c_args = [