configure: reenable opengl by default

Because the opengl library is only linked to for the lm32 target, we can
now safely enable opengl by default again.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

diff --git a/configure b/configure
index 2c95796..35f7e8b 100755 (executable)
--- a/configure
+++ b/configure
@@ -177,7 +177,7 @@ spice=""
 rbd=""
 smartcard=""
 smartcard_nss=""
-opengl="no"
+opengl=""
 
 # parse CC options first
 for opt do