CMake: Prevent qt_remove_args() from accessing out-of-range list index

Pick-to: 6.1
Change-Id: Ie9c5f0551722c7d3fb11879b209c11ce3d7ccd6d
Reviewed-by: Kai Koehne <kai.koehne@qt.io>

cmake/QtCMakeHelpers.cmake

@@ -131,6 +131,10 @@ function(qt_remove_args out_var)
             # remove arg
             list(REMOVE_AT result ${find_result})
             list(LENGTH result result_len)
+            if(find_result EQUAL result_len)
+                # We removed the last argument, could have been an option keyword
+                continue()
+            endif()
             list(GET result ${find_result} arg_current)
             # remove values until we hit another arg or the end of the list
             while(NOT ${arg_current} IN_LIST arg_ALL_ARGS AND find_result LESS result_len)