CMake build creates scanner and parser with debug

[schwehr]

It would be great to have an option to easily enable debug flex and bison output, but I don't think the default should be for debugging builds. lib/CMakeLists.txt has the flex option -d for debug and the bison build has -t for debug. The debug bison build with 3.0.2 on debian testing likes to emit a lot of extra newlines to stderr that I was unable to figure out how to disable.

IF(UNIX)
    add_custom_command(
        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/scanner.c
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
        COMMAND ${UD_FLEX} -d -Put -o scanner.c scanner.l
        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/scanner.l)
    add_custom_command(
        OUTPUT ${CMAKE_CURRENT_SOURCE_DIR}/parser.c
        WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
        COMMAND ${UD_BISON} -t -p ut -o parser.c parser.y
        DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/parser.y)
    set_source_files_properties(parser.c
        PROPERTIES OBJECT_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/scanner.c)
endif()

[schwehr]

5452323 in PR #74