Fix gdkx include path

Fixes #675951

diff --git a/docs/reference/gdk/Makefile.am b/docs/reference/gdk/Makefile.am
index a5bcc768d21bb7a6f4196a8dc6a8e0b8422abfdc..c6ee5facc586bc554de6b15d987583bd0dc512c3 100644 (file)
--- a/docs/reference/gdk/Makefile.am
+++ b/docs/reference/gdk/Makefile.am
@@ -32,9 +32,9 @@ IGNORE_HFILES=                        \
        x11                     \
        quartz
 
-# Extra files to add when scanning (relative to $srcdir)
+# Extra files to add when scanning
 EXTRA_HFILES=                  \
-       ../../../gdk/x11/gdkx.h
+       $(top_srcdir)/gdk/x11/gdkx.h
 
 # CFLAGS and LDFLAGS for compiling scan program. Only needed
 # if $(DOC_MODULE).types is non-empty.