Tseng graphics cards: restore some legacy renderers, fixes Slackware in 4bpp high resolution mode.

src/video/vid_et3000.c

@@ -476,6 +476,9 @@ et3000_recalctimings(svga_t *svga)
             svga->clock = (cpuclock * (double) (1ULL << 32)) / 36000000.0;
             break;
     }
+
+    if (svga->render == svga_render_4bpp_highres)
+        svga->render = svga_render_4bpp_tseng_highres;
 }
 
 static void *

src/video/vid_et4000.c

@@ -723,6 +723,17 @@ et4000_recalctimings(svga_t *svga)
         svga->rowoffset <<= 1;
         svga->render = svga_render_8bpp_highres;
     }
+
+    if (svga->render == svga_render_4bpp_highres)
+        svga->render = svga_render_4bpp_tseng_highres;
+
+    if (dev->type == ET4000_TYPE_TC6058AF) {
+        if (svga->render == svga_render_8bpp_lowres)
+            svga->render = svga_render_8bpp_tseng_lowres;
+
+        else if (svga->render == svga_render_8bpp_highres)
+            svga->render = svga_render_8bpp_tseng_highres;
+    }
 }
 
 static void

src/video/vid_et4000w32.c

@@ -600,6 +600,9 @@ et4000w32p_recalctimings(svga_t *svga)
             }
         }
     }
+
+    if (svga->render == svga_render_4bpp_highres)
+        svga->render = svga_render_4bpp_tseng_highres;
 }
 
 void