Build failure with OpenSSL 1.1.1c on macOS

[fxcoudert]

Building with OpenSSL 1.1.1c on macOS leads to build failure:

/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:405:5: error: use of undeclared identifier 'fd_set'
    fd_set read_set;
    ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:419:18: error: use of undeclared identifier 'read_set'
        FD_ZERO(&read_set);
                 ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:420:28: error: use of undeclared identifier 'read_set'
        FD_SET(ctx->sock, &read_set);
                           ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:422:54: error: use of undeclared identifier 'read_set'
        int select_returned = select(ctx->sock + 1, &read_set, NULL, NULL, &timeout);
                                                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:435:34: error: use of undeclared identifier 'read_set'
        if (FD_ISSET(ctx->sock, &read_set)) {
                                 ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:708:5: error: use of undeclared identifier 'fd_set'
    fd_set write_set, read_set;
    ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:723:22: error: use of undeclared identifier 'write_set'
            FD_ZERO(&write_set);
                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:724:22: error: use of undeclared identifier 'read_set'
            FD_ZERO(&read_set);
                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:725:32: error: use of undeclared identifier 'write_set'
            FD_SET(ctx->sock, &write_set);
                               ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:726:32: error: use of undeclared identifier 'read_set'
            FD_SET(ctx->sock, &read_set);
                               ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:727:54: error: use of undeclared identifier 'read_set'
            select_returned = select(ctx->sock + 1, &read_set, &write_set, NULL, &timeout);
                                                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:727:65: error: use of undeclared identifier 'write_set'
            select_returned = select(ctx->sock + 1, &read_set, &write_set, NULL, &timeout);
                                                                ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:732:33: error: use of undeclared identifier 'read_set'
        __API_SOCKET_READ(ctx, &read_set, apple_error_str, apple_returned_error, 1, i, invalid_token_index)
                                ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:734:34: error: use of undeclared identifier 'write_set'
        if (FD_ISSET(ctx->sock, &write_set)) {
                                 ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:751:22: error: use of undeclared identifier 'read_set'
            FD_ZERO(&read_set);
                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:752:32: error: use of undeclared identifier 'read_set'
            FD_SET(ctx->sock, &read_set);
                               ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:753:54: error: use of undeclared identifier 'read_set'
            select_returned = select(ctx->sock + 1, &read_set, NULL, NULL, &timeout);
                                                     ^
/tmp/libcapn-20190829-36504-1bxg9em/libcapn-2.0.0/src/library/apn.c:758:33: error: use of undeclared identifier 'read_set'
        __API_SOCKET_READ(ctx, &read_set, apple_error_str, apple_returned_error, 0, i, invalid_token_index)
                                ^
18 errors generated.

The build command is:

cmake . -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl@1.1 -DCMAKE_C_FLAGS_RELEASE=-DNDEBUG -DCMAKE_CXX_FLAGS_RELEASE=-DNDEBUG -DCMAKE_INSTALL_PREFIX=/usr/local/Cellar/libcapn/2.0.0_1 -DCMAKE_BUILD_TYPE=Release -DCMAKE_FIND_FRAMEWORK=LAST -DCMAKE_VERBOSE_MAKEFILE=ON -Wno-dev && make install