Fix emp-toolkit build

[marsella]

Build currently fails for emp-tool with errors. This cascades to the rest of the container. Check EMP-toolkit docs for changes to syntax?

In file included from /root/emp-tool/emp-tool/emp-tool.h:15:0,
                 from /root/emp-tool/test/sha3_256.cpp:1:
/root/emp-tool/emp-tool/circuits/sha3_256.h: In function 'int emp::sha3_256(uint8_t*, const T*, size_t)':
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: error: there are no arguments to 'EVP_sha3_256' that depend on a template parameter, so a declaration of 'EVP_sha3_256' must be available [-fpermissive]
  const EVP_MD * algo = EVP_sha3_256();
                                     ^
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
In file included from /root/emp-tool/emp-tool/emp-tool.h:15:0,
                 from /root/emp-tool/test/ecc.cpp:1:
/root/emp-tool/emp-tool/circuits/sha3_256.h: In function 'int emp::sha3_256(uint8_t*, const T*, size_t)':
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: error: there are no arguments to 'EVP_sha3_256' that depend on a template parameter, so a declaration of 'EVP_sha3_256' must be available [-fpermissive]
  const EVP_MD * algo = EVP_sha3_256();
                                     ^
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
In file included from /root/emp-tool/emp-tool/emp-tool.h:15:0,
                 from /root/emp-tool/test/gen_circuit.cpp:1:
/root/emp-tool/emp-tool/circuits/sha3_256.h: In function 'int emp::sha3_256(uint8_t*, const T*, size_t)':
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: error: there are no arguments to 'EVP_sha3_256' that depend on a template parameter, so a declaration of 'EVP_sha3_256' must be available [-fpermissive]
  const EVP_MD * algo = EVP_sha3_256();
                                     ^
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
In file included from /root/emp-tool/emp-tool/circuits/integer.h:69:0,
                 from /root/emp-tool/emp-tool/circuits/float32.h:5,
                 from /root/emp-tool/emp-tool/emp-tool.h:11,
                 from /root/emp-tool/test/hash.cpp:1:
/root/emp-tool/emp-tool/circuits/integer.hpp: In member function 'emp::Integer emp::Integer::operator^=(const emp::Integer&)':
/root/emp-tool/emp-tool/circuits/integer.hpp:263:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(size_t i = 0; i < size(); ++i)
                      ^
In file included from /root/emp-tool/emp-tool/emp-tool.h:15:0,
                 from /root/emp-tool/test/hash.cpp:1:
/root/emp-tool/emp-tool/circuits/sha3_256.h: In function 'int emp::sha3_256(uint8_t*, const T*, size_t)':
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: error: there are no arguments to 'EVP_sha3_256' that depend on a template parameter, so a declaration of 'EVP_sha3_256' must be available [-fpermissive]
  const EVP_MD * algo = EVP_sha3_256();
                                     ^
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:37: note: (if you use '-fpermissive', G++ will accept your code, but allowing the use of an undeclared name is deprecated)
/root/emp-tool/test/gen_circuit.cpp: In function 'void sort(int)':
/root/emp-tool/test/gen_circuit.cpp:28:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(uint64_t i = 0; i < n; ++i) {
                        ^
/root/emp-tool/emp-tool/circuits/sha3_256.h: In instantiation of 'int emp::sha3_256(uint8_t*, const T*, size_t) [with T = unsigned char; uint8_t = unsigned char; size_t = long unsigned int]':
/root/emp-tool/test/sha3_256.cpp:16:42:   required from here
/root/emp-tool/emp-tool/circuits/sha3_256.h:31:36: error: 'EVP_sha3_256' was not declared in this scope
  const EVP_MD * algo = EVP_sha3_256();