transfer routines for compressed formats (avoid SEGFAULT, also prepare for external packers)
diff --git a/src/mesa/main/texformat.c b/src/mesa/main/texformat.c
index 08276d8..9db5364 100644
--- a/src/mesa/main/texformat.c
+++ b/src/mesa/main/texformat.c
@@ -876,7 +876,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgb_fxt1, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */
@@ -898,7 +898,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgba_fxt1, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */
@@ -920,7 +920,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgb_dxt1, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */
@@ -942,7 +942,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgba_dxt1, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */
@@ -964,7 +964,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgba_dxt3, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */
@@ -986,7 +986,7 @@
    0,					/* IndexBits */
    0,					/* DepthBits */
    0,					/* TexelBytes */
-   NULL,				/* StoreTexImageFunc */
+   _mesa_texstore_argb8888,		/* StoreTexImageFunc */
    NULL, /*impossible*/ 		/* FetchTexel1D */
    fetch_texel_2d_rgba_dxt5, 		/* FetchTexel2D */
    NULL, /*impossible*/ 		/* FetchTexel3D */