Compiling/Linking mysql-connector-c++ with CMake on MacOS Catalina

Question

Introduction

I decided to use mysql as part of a project to teach myself C++ so let me apologise in advance for the lack of knowledge. The concept of linking, dynamic and static libraries are still very new to me. With this out of the way, let's proceed.

I'm trying to query a mysql server from C++. Ideally, I'd like the end product to run on any architecture with as little dependencies on libraries as possible. I don't want the user of my code to have to install any libraries themselves (i.e. Connector/C++). I also want to use cmake to compile my project.

Preparation

In order to do this, I used binaries for

mysql-connector-c++-8.0.19-macos10.15-x86-64bit
mysql-8.0.19-macos10.15-x86_64 (wasn't sure whether this was necessary, but mysql documentation said using JDBC to connect to a server requires mysql-client which comes with mysqlserver)

I built Boost from source and I used brew to install openssl even though ssl and crypto dynamic libraries came with the connector binary.

CmakeLists.txt

I used https://dev.mysql.com/doc/connector-cpp/8.0/en/connector-cpp-apps-macos-notes.html and https://dev.mysql.com/doc/connector-cpp/8.0/en/connector-cpp-apps-general-considerations.html#connector-cpp-apps-link-libraries as reference for my CmakeLists.txt

cmake_minimum_required(VERSION 3.1)
project(SQL VERSION 0.1.0)

# enable c++17
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED True)

set(MYSQL_DIR "/usr/local/mysql-connector-c++-8.0.19")

find_package(Threads REQUIRED)
find_package(Boost REQUIRED)
add_executable(${PROJECT_NAME} main.cpp)
target_include_directories(
    ${PROJECT_NAME}
    PUBLIC
    ${MYSQL_DIR}/include
    ${Boost_INCLUDE_DIRS}
)
find_library(SSL_LIB NAMES ssl PATHS ${MYSQL_DIR}/lib64 NO_DEFAULT_PATH)
find_library(CRYPTO_LIB NAMES crypto PATHS ${MYSQL_DIR}/lib64 NO_DEFAULT_PATH)
find_library(MYSQL_LIBS NAMES mysqlcppconn PATHS ${MYSQL_DIR}/lib64)
target_link_libraries(${PROJECT_NAME} ${MYSQL_LIBS} ${SSL_LIB} ${CRYPTO_LIB} Threads::Threads)

C++ Code

#define STATIC_CONCPP
#include 
#include 
#include 
#include 

int main(){
    std::cout << "Connector/C++ standalone program example..." << '
';
    sql::Connection *con;
    sql::Statement *stmt;
    sql::mysql::MySQL_Driver * driver = sql::mysql::get_driver_instance();
    con = driver->connect(URI, USER, PASS);
    con->setSchema(EXAMPLE_DB);
    stmt = con->createStatement();
    sql::ResultSet *res = stmt->executeQuery("SELECT * FROM TICKERS");
    std::cout << "	... running " << "SELECT * FROM TICKERS" << "..." <<'
';
    sql::ResultSetMetaData *mtd = res->getMetaData();
    while (res->next()){
       std::cout << res->getString(1) <<'	' <getString(2) << '
';
    }
}

Results & Questions

I use cmake ..; cmake --build . to build my project.
Using the above, at first I got

Scanning dependencies of target SQL
[ 50%] Building CXX object CMakeFiles/SQL.dir/main.cpp.o
[100%] Linking CXX executable SQL
[100%] Built target SQL

However, why I try and run the executable I get

dyld: Library not loaded: libssl.1.1.dylib
  Referenced from: /Users/paperino/dev/cpp/learn/mysql/build/./SQL
  Reason: image not found
Abort trap: 6

Question1

If I copy libssl and libcrypto from /usr/local/mysql-connector-c++-8.0.19/lib64 to my build folder then I'm able to run the executable. Why is this necessary, even though I've specified the paths to both ssl and crypto libraries using find_library?

Question2

It is possible to link your application with the Connector/C++ static library. This way there is no runtime dependency on the connector, and the resulting binary can run on systems where Connector/C++ is not installed.

Reading this, I thought this sounds exactly like what I want.

I made the following change to my CmakeLists.txt
find_library(MYSQL_LIBS NAMES mysqlcppconn-static PATHS ${MYSQL_DIR}/lib64)

However, trying to build with the static connector library I get the following errors about missing symbols. Any ideas why this is happening and how to fix it?

Scanning dependencies of target SQL
[ 50%] Building CXX object CMakeFiles/SQL.dir/main.cpp.o
[100%] Linking CXX executable SQL
Undefined symbols for architecture x86_64:
  "_res_9_dn_expand", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
  "_res_9_nclose", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
  "_res_9_ninit", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
  "_res_9_ns_initparse", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
  "_res_9_ns_parserr", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
  "_res_9_nsearch", referenced from:
      sql::mysql::srv_list(std::__1::basic_string, std::__1::allocator > const&, unsigned short&) in libmysqlcppconn-static.a(mysql_connection.cpp.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [SQL] Error 1
make[1]: *** [CMakeFiles/SQL.dir/all] Error 2
make: *** [all] Error 2

Thank you all for your time.