replace_include_with_find_package: fix example under mac

example/echo_c++/CMakeLists.txt

@@ -102,15 +102,13 @@ if ((NOT LEVELDB_INCLUDE_PATH) OR (NOT LEVELDB_LIB))
 endif()
 include_directories(${LEVELDB_INCLUDE_PATH})
 
-find_library(SSL_LIB NAMES ssl)
-if (NOT SSL_LIB)
-    message(FATAL_ERROR "Fail to find ssl")
-endif()
-
-find_library(CRYPTO_LIB NAMES crypto)
-if (NOT CRYPTO_LIB)
-    message(FATAL_ERROR "Fail to find crypto")
+if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")
+    set(OPENSSL_ROOT_DIR
+        "/usr/local/opt/openssl"    # Homebrew installed OpenSSL
+        )
 endif()
+include_directories(${OPENSSL_INCLUDE_DIR})
+find_package(OpenSSL)
 
 add_executable(echo_client client.cpp ${PROTO_SRC} ${PROTO_HEADER})
 add_executable(echo_server server.cpp ${PROTO_SRC} ${PROTO_HEADER})
@@ -120,8 +118,8 @@ set(DYNAMIC_LIB
     ${GFLAGS_LIBRARY}
     ${PROTOBUF_LIBRARIES}
     ${LEVELDB_LIB}
-    ${SSL_LIB}
-    ${CRYPTO_LIB}
+    ${OPENSSL_CRYPTO_LIBRARY}
+    ${OPENSSL_SSL_LIBRARY}
     ${THRIFT_LIB}
     ${THRIFTNB_LIB}
     dl