Partially revert 9bb3235

The -DCMAKE_POSITION_INDEPENDENT_CODE=ON resolves to -fPIE instead
of -fPIC (on some platforms?) rendering cmake broken.

cmake/QCAMacros.cmake

@@ -13,7 +13,7 @@
 function(FIND_QCAOSSL_PLUGIN_CPP PLUGIN_REQUIRED)
 
   # requires Qt and QCA packages to be found
-  if(QT_INCLUDES AND Qt5Core_LIBRARIES
+  if(QT_INCLUDE_DIR AND QT_QTCORE_INCLUDE_DIR AND QT_QTCORE_LIBRARY
      AND QCA_INCLUDE_DIR AND QCA_LIBRARY
      AND NOT CMAKE_CROSSCOMPILING)