How do you add CFLAGS to cmake to look for dependencies locally?

I'm trying to install C++ web framework, drogon, which requires following steps to install.

cd $WORK_PATH
git clone https://github.com/drogonframework/drogon
cd drogon
git submodule update --init
mkdir build
cd build
cmake ..
make && sudo make install

To install locally, I added the following command option,
cmake --install-prefix=$HOME/local.

However, the make process ended up like this,

/bin/ld: ../trantor/libtrantor.a(OpenSSLProvider.cc.o): in function `OpenSSLProvider::processHandshake()':
OpenSSLProvider.cc:(.text._ZN15OpenSSLProvider16processHandshakeEv[_ZN15OpenSSLProvider16processHandshakeEv]+0x504): undefined reference to `SSL_get1_peer_certificate'
/bin/ld: ../trantor/libtrantor.a(openssl.cc.o): in function `trantor::utils::md5(void const*, unsigned long)':
openssl.cc:(.text+0x35): undefined reference to `EVP_MD_fetch'
/bin/ld: openssl.cc:(.text+0xa1): undefined reference to `EVP_MD_free'
/bin/ld: ../trantor/libtrantor.a(openssl.cc.o): in function `trantor::utils::sha1(void const*, unsigned long)':
openssl.cc:(.text+0xfc): undefined reference to `EVP_MD_fetch'
/bin/ld: openssl.cc:(.text+0x168): undefined reference to `EVP_MD_free'
/bin/ld: ../trantor/libtrantor.a(openssl.cc.o): in function `trantor::utils::sha256(void const*, unsigned long)':
openssl.cc:(.text+0x1c0): undefined reference to `EVP_MD_fetch'
/bin/ld: openssl.cc:(.text+0x22c): undefined reference to `EVP_MD_free'
/bin/ld: ../trantor/libtrantor.a(openssl.cc.o): in function `trantor::utils::sha3(void const*, unsigned long)':
openssl.cc:(.text+0x284): undefined reference to `EVP_MD_fetch'
/bin/ld: openssl.cc:(.text+0x2f0): undefined reference to `EVP_MD_free'
/bin/ld: ../trantor/libtrantor.a(openssl.cc.o): in function `trantor::utils::blake2b(void const*, unsigned long)':
openssl.cc:(.text+0x348): undefined reference to `EVP_MD_fetch'
/bin/ld: openssl.cc:(.text+0x3b4): undefined reference to `EVP_MD_free'
collect2: error: ld returned 1 exit status
make[2]: *** [examples/CMakeFiles/client.dir/build.make:105: examples/client] Error 1
make[1]: *** [CMakeFiles/Makefile2:293: examples/CMakeFiles/client.dir/all] Error 2

That error is because of the older OpenSSL version the system has, according to cmake output.

Found OpenSSL: /usr/lib/x86_64-linux-gnu/libcrypto.so (found version "1.1.1f")  

So I installed newest version (https://www.openssl.org/source/) local ($HOEM/.local) as well.

The OpenSSL installation was successful but when I tried the drogon installation again, I got bounced off at the same step make with same error.
Even cmake produced the same output as above for the OpenSSL path and its version.

My question is how do you make cmake look for stuff locally ?
Like other installation process like ./configure, you can add CFLAGS="-I/usr/local/include option.
Is there similar method to cmake ?

In general it depends on how the CMake projects is searching for its dependencies. If the project uses find_package(<Package>), in many cases you can set a variable <Package>_ROOT to point to the installation prefix of the package. In the case of OpenSSL you'll need to use OPENSSL_ROOT_DIR as documented here.

So you need to configure the project with

cmake -DOPENSSL_ROOT_DIR=${HOME}/.local ..

after deleting the build directory.