[truetype] Relocate subpixel flag setting.

`TT_RunIns` is too busy to deal with subpixel flags. It is better
to set them in `tt_loader_init`, which is executed before each
glyph program.

* src/truetype/ttinterp.c (TT_RunIns): Move the flag setting from
here...
* src/truetype/ttgload.c (tt_loader_init): ... to here.

src/truetype/ttgload.c

@@ -2719,8 +2719,35 @@
       /* note that this flag can also be modified in a glyph's bytecode */
       if ( driver->interpreter_version == TT_INTERPRETER_VERSION_38 &&
            exec->GS.instruct_control & 4                            )
-        exec->ignore_x_mode = 0;
-#endif
+        exec->ignore_x_mode = FALSE;
+
+      exec->iup_called = FALSE;
+#endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
+
+#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
+      /*
+       * Toggle backward compatibility according to what font wants, except
+       * when
+       *
+       * 1) we have a `tricky' font that heavily relies on the interpreter to
+       *    render glyphs correctly, for example DFKai-SB, or
+       * 2) FT_RENDER_MODE_MONO (i.e, monochome rendering) is requested.
+       *
+       * In those cases, backward compatibility needs to be turned off to get
+       * correct rendering.  The rendering is then completely up to the
+       * font's programming.
+       *
+       */
+      if ( driver->interpreter_version == TT_INTERPRETER_VERSION_40 &&
+           subpixel_hinting_lean                                    &&
+           !FT_IS_TRICKY( glyph->face )                             )
+        exec->backward_compatibility = !( exec->GS.instruct_control & 4 );
+      else
+        exec->backward_compatibility = FALSE;
+
+      exec->iupx_called = FALSE;
+      exec->iupy_called = FALSE;
+#endif /* TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL */
 
       exec->pedantic_hinting = FT_BOOL( load_flags & FT_LOAD_PEDANTIC );
       loader->exec = exec;

src/truetype/ttinterp.c

@@ -7762,35 +7762,6 @@
 #endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
 
 
-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY
-    exc->iup_called = FALSE;
-#endif /* TT_SUPPORT_SUBPIXEL_HINTING_INFINALITY */
-
-#ifdef TT_SUPPORT_SUBPIXEL_HINTING_MINIMAL
-    /*
-     * Toggle backward compatibility according to what font wants, except
-     * when
-     *
-     * 1) we have a `tricky' font that heavily relies on the interpreter to
-     *    render glyphs correctly, for example DFKai-SB, or
-     * 2) FT_RENDER_MODE_MONO (i.e, monochome rendering) is requested.
-     *
-     * In those cases, backward compatibility needs to be turned off to get
-     * correct rendering.  The rendering is then completely up to the
-     * font's programming.
-     *
-     */
-    if ( SUBPIXEL_HINTING_MINIMAL          &&
-         exc->subpixel_hinting_lean        &&
-         !FT_IS_TRICKY( &exc->face->root ) )
-      exc->backward_compatibility = !( exc->GS.instruct_control & 4 );
-    else
-      exc->backward_compatibility = FALSE;
-
-    exc->iupx_called = FALSE;
-    exc->iupy_called = FALSE;
-#endif
-
     /* We restrict the number of twilight points to a reasonable,     */
     /* heuristic value to avoid slow execution of malformed bytecode. */
     num_twilight_points = FT_MAX( 30,