Fix ABI incompatibility.

* include/freetype/ftimage.h (FT_Pixel_Mode): Don't insert
`FT_PIXEL_MODE_GRAY16' but append it.

* src/base/ftobjs.c (pixel_modes): Updated.
diff --git a/ChangeLog b/ChangeLog
index b8be2cd..85f431d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2021-01-07  Werner Lemberg  <wl@gnu.org>
+
+	Fix ABI incompatibility.
+
+	* include/freetype/ftimage.h (FT_Pixel_Mode): Don't insert
+	`FT_PIXEL_MODE_GRAY16' but append it.
+
+	* src/base/ftobjs.c (pixel_modes): Updated.
+
 2021-01-07  Alexei Podtelezhnikov  <apodtele@gmail.com>
 
 	[dlg] Move the headers to include/dlg to simplify their use.
diff --git a/include/freetype/ftimage.h b/include/freetype/ftimage.h
index 0aee7f0..5b6d348 100644
--- a/include/freetype/ftimage.h
+++ b/include/freetype/ftimage.h
@@ -191,10 +191,10 @@
     FT_PIXEL_MODE_GRAY,
     FT_PIXEL_MODE_GRAY2,
     FT_PIXEL_MODE_GRAY4,
-    FT_PIXEL_MODE_GRAY16,
     FT_PIXEL_MODE_LCD,
     FT_PIXEL_MODE_LCD_V,
     FT_PIXEL_MODE_BGRA,
+    FT_PIXEL_MODE_GRAY16,
 
     FT_PIXEL_MODE_MAX      /* do not remove */
 
diff --git a/src/base/ftobjs.c b/src/base/ftobjs.c
index 65c37e1..bf6f3d4 100644
--- a/src/base/ftobjs.c
+++ b/src/base/ftobjs.c
@@ -88,10 +88,10 @@
     "gray 8-bit bitmap",
     "gray 2-bit bitmap",
     "gray 4-bit bitmap",
-    "SDF 16-bit bitmap",
     "LCD 8-bit bitmap",
     "vertical LCD 8-bit bitmap",
     "BGRA 32-bit color image bitmap"
+    "SDF 16-bit bitmap",
   };
 
 #endif /* FT_DEBUG_LEVEL_TRACE */