[autoconf] Refine doxygen document options.

This CL adds --enable-doxygen-search to enable doxygen search engine
and --enable-doxygen-qt-help to enable the Qt help file generation.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232062 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed