besides that shell scripts are not executable and secp256k1 build returns compilation errors too? (when replaced by original one it works)
src/bignum.h: In function ‘bool operator>=(const CBigNum&, const CBigNum&)’:
src/bignum.h:718:83: error: cannot convert ‘const CBigNum*’ to ‘const BIGNUM* {aka const bignum_st*}’ for argument ‘1’ to ‘int BN_cmp(const BI NUM*, const BIGNUM*)’
inline bool operator>=(const CBigNum& a, const CBigNum& b) { return (BN_cmp(&a, &b) >= 0); }
^