gallium/swr: allow swr use as a swrast dri driver

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Tested-by: Ilia Mirkin <imirkin@alum.mit.edu>
diff --git a/configure.ac b/configure.ac
index 4313aff..4a41d8f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2378,6 +2378,9 @@
 AM_CONDITIONAL(HAVE_GALLIUM_SOFTPIPE, test "x$HAVE_GALLIUM_SOFTPIPE" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_LLVMPIPE, test "x$HAVE_GALLIUM_LLVMPIPE" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_SWR, test "x$HAVE_GALLIUM_SWR" = xyes)
+AM_CONDITIONAL(HAVE_GALLIUM_SWRAST, test "x$HAVE_GALLIUM_SOFTPIPE" = xyes -o \
+                                         "x$HAVE_GALLIUM_LLVMPIPE" = xyes -o \
+                                         "x$HAVE_GALLIUM_SWR" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_VC4, test "x$HAVE_GALLIUM_VC4" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_VIRGL, test "x$HAVE_GALLIUM_VIRGL" = xyes)