Ruby 3.0.0とMySQL 5.7がbooklistフォルダにインストールされてるのにmysql2をインストールできない。

Question

使用環境がRuby 3.0.0、 MySQL 5.7、Homebrew 3.0.5です。使用機器がmacOSです。

mysql2でRubyとMySQLを連携させていただくために、
mysql2のインストールコマンド(以下のコマンド)を入力させて頂きました。

$ gem install mysql2

そしたら以下のようなエラーが出ました。

Building native extensions. This could take a while...
ERROR:  Error installing mysql2:
        ERROR: Failed to build gem native extension.

    current directory: /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
/Users/ユーザ名/.rbenv/versions/3.0.0/bin/ruby -I /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/3.0.0 -r ./siteconf20210317-69500-owpcwc.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes
-----
Using mysql_config at /usr/local/opt/mysql@5.7/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for SSL_MODE_DISABLED in mysql.h... yes
checking for SSL_MODE_PREFERRED in mysql.h... yes
checking for SSL_MODE_REQUIRED in mysql.h... yes
checking for SSL_MODE_VERIFY_CA in mysql.h... yes
checking for SSL_MODE_VERIFY_IDENTITY in mysql.h... yes
checking for MYSQL.net.vio in mysql.h... yes
checking for MYSQL.net.pvio in mysql.h... no
checking for MYSQL_ENABLE_CLEARTEXT_PLUGIN in mysql.h... yes
checking for SERVER_QUERY_NO_GOOD_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_NO_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_WAS_SLOW in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_ON in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_OFF in mysql.h... yes
checking for my_bool in mysql.h... yes
-----
Don't know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load
-----
-----
Setting libpath to /usr/local/opt/mysql@5.7/lib
-----
creating Makefile

current directory: /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
make "DESTDIR=" clean

current directory: /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3/ext/mysql2
make "DESTDIR="
compiling client.c
client.c:787:14: warning: incompatible pointer types passing 'VALUE (void *)' (aka 'unsigned long (void *)') to parameter of type 'VALUE (*)(VALUE)' (aka 'unsigned long
(*)(unsigned long)') [-Wincompatible-pointer-types]
  rb_rescue2(do_send_query, (VALUE)&args, disconnect_and_raise, self, rb_eException, (VALUE)0);

             ^~~~~~~~~~~~~
/Users/ユーザ名/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby/internal/iterator.h:51:25: note: passing argument to parameter here
VALUE rb_rescue2(VALUE(*)(VALUE),VALUE,VALUE(*)(VALUE,VALUE),VALUE,...);
                        ^
client.c:795:16: warning: incompatible pointer types passing 'VALUE (void *)' (aka 'unsigned long (void *)') to parameter of type 'VALUE (*)(VALUE)' (aka 'unsigned long
(*)(unsigned long)') [-Wincompatible-pointer-types]
    rb_rescue2(do_query, (VALUE)&async_args, disconnect_and_raise, self, rb_eException, (VALUE)0);
               ^~~~~~~~
/Users/ユーザ名/.rbenv/versions/3.0.0/include/ruby-3.0.0/ruby/internal/iterator.h:51:25: note: passing argument to parameter here
VALUE rb_rescue2(VALUE(*)(VALUE),VALUE,VALUE(*)(VALUE,VALUE),VALUE,...);
                        ^
2 warnings generated.
compiling infile.c
compiling mysql2_ext.c
compiling result.c
compiling statement.c
linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/gems/mysql2-0.5.3 for inspection.
Results logged to /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/extensions/x86_64-darwin-17/3.0.0/mysql2-0.5.3/gem_make.out

Answer 1

Results logged to /Users/ユーザ名/.rbenv/versions/3.0.0/lib/ruby/gems/3.0.0/extensions/x86_64-darwin-17/3.0.0/mysql2-0.5.3/gem_make.out
とあります。これを確認してください。
何が悪かったかが書かれています。で、おそらく、どうしたらよいかも書かれています。