Remove executable bit from secp256k1.c
Remove executable bit from secp256k1.c

pmienk/secp256k1,bitcoin/secp256k1,voisine/secp256k1,voisine/secp256k1,voisine/secp256k1,digitalbitbox/secp256k1,evoskuil/secp256k1,digitalbitbox/secp256k1,bitcoin-core/secp256k1,apoelstra/secp256k1,bitcoin-core/secp256k1,digitalbitbox/secp256k1,bitcoin/secp256k1,peterdettman/secp256k1,evoskuil/secp256k1,apoelstra/secp256k1,bitcoin/secp256k1,afk11/secp256k1,bitcoin/secp256k1,apoelstra/secp256k1,pmienk/secp256k1,voisine/secp256k1,peterdettman/secp256k1,afk11/secp256k1,libbitcoin/secp256k1,libbitcoin/secp256k1,pmienk/secp256k1,pmienk/secp256k1,evoskuil/secp256k1,afk11/secp256k1,digitalbitbox/secp256k1,afk11/secp256k1,pmienk/secp256k1,libbitcoin/secp256k1,ElementsProject/secp256k1-zkp,voisine/secp256k1,evoskuil/secp256k1,apoelstra/secp256k1,bitcoin/secp256k1,apoelstra/secp256k1,afk11/secp256k1,libbitcoin/secp256k1,evoskuil/secp256k1,ElementsProject/secp256k1-zkp,libbitcoin/secp256k1,digitalbitbox/secp256k1