Write qt.conf only if no QTROOT variable supplied

This will make sure that the qt.conf file is only written if no QTROOT variable is passed to cmake. It will allow building on Linux with non-root accounts when the QTROOT points to a priviliged folder on the system.

This has been discussed in issue #276.

Plex-CLA-1.0-signed-off-by: Niclas Berglind <nb@kjam.se>

CMakeModules/QtConfiguration.cmake

@@ -15,18 +15,17 @@ if(NOT IS_DIRECTORY ${QTROOT})
     DYLIB_SCRIPT_PATH ${PROJECT_SOURCE_DIR}/scripts/fix-install-names.py
 	)
   set(QTROOT ${dir})
+  
+  # Write qt.conf in the Qt depends directory so that the Qt tools can find QML files
+  set(QTCONFCONTENT "[Paths]
+    Prefix=${QTROOT}
+    ")
+  file(WRITE ${QTROOT}/bin/qt.conf ${QTCONFCONTENT})
 endif()
 list(APPEND CMAKE_FIND_ROOT_PATH ${QTROOT})
 list(APPEND CMAKE_PREFIX_PATH ${QTROOT})
 include_directories(${QTROOT}/include)
 
-# Write qt.conf in the Qt depends directory so that the Qt tools can find QML files
-set(QTCONFCONTENT "[Paths]
-Prefix=${QTROOT}
-")
-
-file(WRITE ${QTROOT}/bin/qt.conf ${QTCONFCONTENT})
-
 set(REQUIRED_QT_VERSION "5.6.0")
 
 message(STATUS ${QTROOT})