Fix ssl cmake configuration not checking for symbols properly

Both libraries and includes are required to check for symbols correctly.

In addition, we don't use SHA512_DIGEST_LENGTH symbol so remove the
extraneous check.

cmake/ssl.cmake

@@ -129,10 +129,6 @@ MACRO (MYSQL_CHECK_SSL)
     IF(OPENSSL_FOUND)
       SET(OPENSSL_LIBRARY ${OPENSSL_SSL_LIBRARY})
       INCLUDE(CheckSymbolExists)
-      SET(CMAKE_REQUIRED_INCLUDES ${OPENSSL_INCLUDE_DIR})
-      CHECK_SYMBOL_EXISTS(SHA512_DIGEST_LENGTH "openssl/sha.h"
-                          HAVE_SHA512_DIGEST_LENGTH)
-      SET(CMAKE_REQUIRED_INCLUDES)
       SET(SSL_SOURCES "")
       SET(SSL_LIBRARIES ${OPENSSL_SSL_LIBRARY} ${OPENSSL_CRYPTO_LIBRARY})
       IF(CMAKE_SYSTEM_NAME MATCHES "SunOS")
@@ -151,6 +147,7 @@ MACRO (MYSQL_CHECK_SSL)
       SET(SSL_INTERNAL_INCLUDE_DIRS "")
       SET(SSL_DEFINES "-DHAVE_OPENSSL")
 
+      SET(CMAKE_REQUIRED_INCLUDES ${OPENSSL_INCLUDE_DIR})
       SET(CMAKE_REQUIRED_LIBRARIES ${SSL_LIBRARIES})
       CHECK_SYMBOL_EXISTS(ERR_remove_thread_state "openssl/err.h"
                           HAVE_ERR_remove_thread_state)
@@ -158,6 +155,8 @@ MACRO (MYSQL_CHECK_SSL)
                           HAVE_EncryptAes128Ctr)
       CHECK_SYMBOL_EXISTS(EVP_aes_128_gcm "openssl/evp.h"
                           HAVE_EncryptAes128Gcm)
+      SET(CMAKE_REQUIRED_INCLUDES)
+      SET(CMAKE_REQUIRED_LIBRARIES)
     ELSE()
       IF(WITH_SSL STREQUAL "system")
         MESSAGE(SEND_ERROR "Cannot find appropriate system libraries for SSL. Use WITH_SSL=bundled to enable SSL support")