Change ENABLE_TESTS to WITH_TESTS in GSL.
Change ENABLE_TESTS to WITH_TESTS in GSL.

cancoin/libbitcoin-explorer,GroestlCoin/libgroestlcoin-explorer,GroestlCoin/libgroestlcoin-explorer,libmetrocoin/libmetrocoin-explorer,libtetcoin/libtetcoin-explorer,libtetcoin/libtetcoin-explorer,GroestlCoin/libgroestlcoin-explorer,tuomassiren/libbitcoin-explorer,tuomassiren/libbitcoin-explorer,libmetrocoin/libmetrocoin-explorer,cancoin/libbitcoin-explorer