Use CMake features to search for OpenSSL libraries

Signed-off-by: Otavio Rodolfo Piske <opiske@redhat.com>

src/CMakeLists.txt

 #*******************************************************************************
 #  Copyright (c) 2015 logi.cals GmbH
-# 
+#
 #  All rights reserved. This program and the accompanying materials
 #  are made available under the terms of the Eclipse Public License v1.0
-#  and Eclipse Distribution License v1.0 which accompany this distribution. 
-# 
-#  The Eclipse Public License is available at 
+#  and Eclipse Distribution License v1.0 which accompany this distribution.
+#
+#  The Eclipse Public License is available at
 #     http://www.eclipse.org/legal/epl-v10.html
-#  and the Eclipse Distribution License is available at 
+#  and the Eclipse Distribution License is available at
 #    http://www.eclipse.org/org/documents/edl-v10.php.
-# 
+#
 #  Contributors:
 #     Rainer Poisel - initial version
 #*******************************************************************************/
@@ -56,7 +56,7 @@ ENDIF()
 ADD_EXECUTABLE(MQTTVersion MQTTVersion.c)
 ADD_LIBRARY(paho-mqtt3c SHARED ${common_src} MQTTClient.c)
 ADD_LIBRARY(paho-mqtt3a SHARED ${common_src} MQTTAsync.c)
-TARGET_LINK_LIBRARIES(paho-mqtt3c pthread ${LIBS_SYSTEM}) 
+TARGET_LINK_LIBRARIES(paho-mqtt3c pthread ${LIBS_SYSTEM})
 TARGET_LINK_LIBRARIES(paho-mqtt3a pthread ${LIBS_SYSTEM})
 TARGET_LINK_LIBRARIES(MQTTVersion paho-mqtt3a paho-mqtt3c ${LIBS_SYSTEM})
 SET_TARGET_PROPERTIES(
@@ -70,19 +70,30 @@ INSTALL(FILES MQTTAsync.h MQTTClient.h MQTTClientPersistence.h
     DESTINATION include)
 
 IF (PAHO_WITH_SSL)
-    SET(OPENSSL_LIB_SEARCH_PATH "" CACHE PATH "Directory containing OpenSSL libraries")
+SET(OPENSSL_LIB_SEARCH_PATH "" CACHE PATH "Directory containing OpenSSL libraries")
     SET(OPENSSL_INC_SEARCH_PATH "" CACHE PATH "Directory containing OpenSSL includes")
     SET(OPENSSL_LIBRARIES ssl crypto)
-    LINK_DIRECTORIES(
-        ${OPENSSL_LIB_SEARCH_PATH}
-        )
+
+    find_path(OPENSSL_INCLUDE_DIR openssl/ssl.h
+	HINTS ${OPENSSL_INC_SEARCH_PATH}/include)
+    find_library(OPENSSL_LIB NAMES ssl libssl
+	HINTS ${OPENSSL_DIR}/lib ${OPENSSL_DIR}/lib64)
+    find_library(OPENSSLCRYPTO_LIB NAMES ssl libssl
+	HINTS ${OPENSSL_DIR}/lib ${OPENSSL_DIR}/lib64)
+
+    message(STATUS "OpenSSL hint ${PENSSL_INC_SEARCH_PATH} (includes) / ")
+    message(STATUS "OpenSSL headers found at ${OPENSSL_INCLUDE_DIR}")
+    message(STATUS "OpenSSL library found at ${OPENSSL_LIB}")
+    message(STATUS "OpenSSL Crypto library found at ${OPENSSLCRYPTO_LIB}")
+
     INCLUDE_DIRECTORIES(
-        ${OPENSSL_INC_SEARCH_PATH}
-        )
+        ${OPENSSL_INCLUDE_DIR}
+    )
     ADD_LIBRARY(paho-mqtt3cs SHARED ${common_src} MQTTClient.c SSLSocket.c)
     ADD_LIBRARY(paho-mqtt3as SHARED ${common_src} MQTTAsync.c SSLSocket.c)
-    TARGET_LINK_LIBRARIES(paho-mqtt3cs pthread ${OPENSSL_LIBRARIES} ${LIBS_SYSTEM})
-    TARGET_LINK_LIBRARIES(paho-mqtt3as pthread ${OPENSSL_LIBRARIES} ${LIBS_SYSTEM})
+
+    TARGET_LINK_LIBRARIES(paho-mqtt3cs pthread ${OPENSSL_LIB} ${OPENSSLCRYPTO_LIB} ${LIBS_SYSTEM})
+    TARGET_LINK_LIBRARIES(paho-mqtt3as pthread ${OPENSSL_LIB} ${OPENSSLCRYPTO_LIB} ${LIBS_SYSTEM})
     SET_TARGET_PROPERTIES(
         paho-mqtt3cs paho-mqtt3as PROPERTIES
         VERSION ${CLIENT_VERSION}