llvm3.3: append --enable-zlib to EXTRA_OECONF instead of overwriting
The options added to EXTRA_OECONF in llvm3.inc were being overwritten
with --enable-zlib in llvm3.3_3.3.bb.
Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>