[libcalamares] Apply Qt defines consistently

- Move some definitions that influence Qt compilation
  up to the top-level.

CMakeLists.txt

@@ -496,7 +496,11 @@ if ( CALAMARES_VERSION_RC EQUAL 0 )
 endif()
 
 # enforce using constBegin, constEnd for const-iterators
-add_definitions( "-DQT_STRICT_ITERATORS" )
+add_definitions(
+    -DQT_STRICT_ITERATORS
+    -DQT_SHARED
+    -DQT_SHAREDPOINTER_TRACK_POINTERS
+)
 
 # set paths
 set( CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}" )

src/libcalamares/CMakeLists.txt

@@ -1,12 +1,7 @@
 # libcalamares is the non-GUI part of Calamares, which includes handling
 # translations, configurations, logging, utilities, global storage, and (non-GUI) jobs.
 
-add_definitions(
-    ${QT_DEFINITIONS}
-    -DQT_SHARED
-    -DQT_SHAREDPOINTER_TRACK_POINTERS
-    -DDLLEXPORT_PRO
-)
+add_definitions( -DDLLEXPORT_PRO )
 
 configure_file( ${CMAKE_CURRENT_SOURCE_DIR}/CalamaresConfig.h.in
                 ${CMAKE_CURRENT_BINARY_DIR}/CalamaresConfig.h )