svga: Do the gallium intel configure trick for svga as well

Since the drivers we produce on systems where we use
configure depend on none stable kernel API the driver
deliverables should not be built by default in the
mesa 7.7 release.

People wishing to shoot them self in the foot have to
pull the trigger themself, we just hand them the gun.

configure.ac

@@ -1200,13 +1200,15 @@ dnl
 dnl Gallium SVGA configuration
 dnl
 AC_ARG_ENABLE([gallium-svga],
-    [AS_HELP_STRING([--disable-gallium-svga],
-        [build gallium SVGA @<:@default=enabled@:>@])],
+    [AS_HELP_STRING([--enable-gallium-svga],
+        [build gallium SVGA @<:@default=disabled@:>@])],
     [enable_gallium_svga="$enableval"],
-    [enable_gallium_svga=yes])
+    [enable_gallium_svga=auto])
 if test "x$enable_gallium_svga" = xyes; then
     GALLIUM_WINSYS_DRM_DIRS="$GALLIUM_WINSYS_DRM_DIRS vmware"
     GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS svga"
+elif test "x$enable_gallium_svga" = xauto; then
+    GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS svga"
 fi
 
 dnl