bootanimation: build 32-bit if 64-bit gl libraries are not available

Set LOCAL_32_BIT_ONLY if TARGET_32_BIT_SURFACEFLINGER is set.

Change-Id: I76396cc9fe3fe45d1e98a44bf911d6e70922555a
diff --git a/cmds/bootanimation/Android.mk b/cmds/bootanimation/Android.mk
index d5ff84e..dd987e0 100644
--- a/cmds/bootanimation/Android.mk
+++ b/cmds/bootanimation/Android.mk
@@ -24,5 +24,8 @@
 
 LOCAL_MODULE:= bootanimation
 
+ifdef TARGET_32_BIT_SURFACEFLINGER
+LOCAL_32_BIT_ONLY := true
+endif
 
 include $(BUILD_EXECUTABLE)