gdi: Use correct include file for FT_Get_Module.
diff --git a/configure.ac b/configure.ac
index ca5eb8a..761f528 100644
--- a/configure.ac
+++ b/configure.ac
@@ -596,6 +596,7 @@
                          freetype/ttnameid.h \
                          freetype/ftoutln.h \
                          freetype/ftwinfnt.h \
+                         freetype/ftmodapi.h \
                          freetype/internal/sfnt.h,,,
                          [#if HAVE_FT2BUILD_H
                           #include <ft2build.h>