[docs] Introduce ExternalProjectsUsingClang.rst

A couple concrete examples are sure to be a win. If you know of any
other external projects using Clang, please let me know!

Patch by Laszlo Nagy! (with a title tweak by me)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@175529 91177308-0d34-0410-b5e6-96231b3b80d8

docs/ExternalProjectsUsingClang.rst

+=============================
+External Projects Using Clang
+=============================
+
+Clang is more than a compiler; its library-based approach allows creation of
+different kinds of tools that can process source code.
+
+This page contains references to Clang based tools and projects. To extend
+the list you could write email to the `development mailing list
+<http://lists.cs.uiuc.edu/mailman/listinfo/cfe-dev>`_.
+
+List of projects and tools
+==========================
+
+`<https://github.com/etaoins/qconnectlint>`_
+   "qconnectlint is a Clang tool for statically verifying the consistency
+   of signal and slot connections made with Qt's ``QObject::connect``."
+
+`<https://github.com/woboq/woboq_codebrowser>`_
+   "The Woboq Code Browser is a web-based code browser for C/C++ projects.
+   Check out `<http://code.woboq.org/>`_ for an example!"
+
+`<https://github.com/mozilla/dxr>`_
+    "DXR is a source code cross-reference tool that uses static analysis
+    data collected by instrumented compilers."
+
+`<https://github.com/eschulte/clang-mutate>`_
+    "This tool performs a number of operations on C-language source files."
+
+`<https://github.com/gmarpons/Crisp>`_
+    "A coding rule validation add-on for LLVM/clang. Crisp rules are written
+    in Prolog. A high-level declarative DSL to easily write new rules is under
+    development. It will be called CRISP, an acronym for *Coding Rules in
+    Sugared Prolog*."
+
+`<https://github.com/drothlis/clang-ctags>`_
+    "Generate tag file for C++ source code."
+
+`<https://github.com/exclipy/clang_indexer>`_
+    "This is an indexer for C and C++ based on the libclang library."
+
+`<https://github.com/holtgrewe/linty>`_
+    "Linty - C/C++ Style Checking with Python & libclang."
+
+`<https://github.com/axw/cmonster>`_
+    "cmonster is a Python wrapper for the Clang C++ parser."
+
+`<https://github.com/rizsotto/Constantine>`_
+    "Constantine is a toy project to learn how to write clang plugin.  
+    Implements pseudo const analysis. Generates warnings about variables,
+    which were declared without const qualifier."
+
+`<https://github.com/jessevdk/cldoc>`_
+    "cldoc is a Clang based documentation generator for C and C++.
+    cldoc tries to solve the issue of writing C/C++ software documentation
+    with a modern, non-intrusive and robust approach."

docs/index.rst

@@ -30,6 +30,7 @@ Using Clang as a Library
    :maxdepth: 1
 
    Tooling
+   ExternalProjectsUsingClang
    IntroductionToTheClangAST
    LibTooling
    LibFormat