Allow openssl detection without pkg-config file

Signed-off-by: Slávek Banko <slavek.banko@...>

diff --git a/CMakeLists.txt b/CMakeLists.txt
index cf1cb11..ecacb26 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -981,7 +981,15 @@
 if( WITH_SSL )
   pkg_search_module( SSL openssl )
   if( NOT SSL_FOUND )
-    message(FATAL_ERROR "\nSSL support are requested, but openssl is not found on your system" )
+    check_include_file( openssl/ssl.h HAVE_OPENSSL_H )
+    check_library_exists( ssl SSL_library_init "" HAVE_LIBSSL )
+    check_library_exists( crypto EVP_EncryptInit_ex "" HAVE_LIBCRYPTO )
+    if( HAVE_OPENSSL_H AND HAVE_LIBSSL AND HAVE_LIBCRYPTO )
+      set( SSL_FOUND 1 CACHE INTERNAL "" FORCE )
+    endif( HAVE_OPENSSL_H AND HAVE_LIBSSL AND HAVE_LIBCRYPTO )
+  endif( NOT SSL_FOUND )
+  if( NOT SSL_FOUND )
+    tde_message_fatal( "SSL support is requested, but openssl not found on your system" )
   endif( NOT SSL_FOUND )
   set( KSSL_HAVE_SSL 1 )
   set( HAVE_SSL 1 )