T1_Open_Face now tolerates a face with no charstrings if there is

an incremental loading interface. This is essential if incremental
loading of Type 1 fonts supplied by PostScript is to work.

src/type1/t1load.c

@@ -1711,11 +1711,14 @@
       type1->subrs_len   = loader.subrs.lengths;
     }
 
-    if ( !loader.charstrings.init )
-    {
-      FT_ERROR(( "T1_Open_Face: no charstrings array in face!\n" ));
-      error = T1_Err_Invalid_File_Format;
-    }
+#ifdef FT_CONFIG_OPTION_INCREMENTAL
+    if (!face->root.internal->incremental_interface)
+#endif
+      if ( !loader.charstrings.init )
+      {
+        FT_ERROR(( "T1_Open_Face: no charstrings array in face!\n" ));
+        error = T1_Err_Invalid_File_Format;
+      }
 
     loader.charstrings.init  = 0;
     type1->charstrings_block = loader.charstrings.block;