Update README.md to remove autoconf instructions in favor of cmake.

diff --git a/README.md b/README.md
index 73617299acfb1c552da0b9bfe3b3aecf9f7a8ea8..addd3643407af4ec8f6ea23284f31ec8f8ae4f8b 100644 (file)
--- a/README.md
+++ b/README.md
@@ -3,9 +3,11 @@
 
 1. [Overview and Build Status](#overview)
 2. [Building on Unix](#buildunix)
-3. [Install Prerequisites](#installprereq)
-4. [Building with partial threading support](#buildthreaded)
-5. [Building with CMake](#CMake)
+    * [Prerequisites](#installprereq)
+    * [Build commands](#buildcmds)
+3. [CMake options](#CMake)
+4. [Testing](#testing)
+5. [Building with `vcpkg`](#buildvcpkg)
 6. [Linking to libjson-c](#linking)
 7. [Using json-c](#using)
 
@@ -24,116 +26,90 @@ construct JSON objects in C, output them as JSON formatted strings and parse
 JSON formatted strings back into the C representation of JSON objects.
 It aims to conform to [RFC 7159](https://tools.ietf.org/html/rfc7159).
 
-Building on Unix and Windows with `vcpkg`, `gcc`/`g++`, `curl`, `unzip`, and `tar`
---------------------------------------------------
-
-You can download and install JSON-C using the [vcpkg](https://github.com/Microsoft/vcpkg/) dependency manager:
-
-    git clone https://github.com/Microsoft/vcpkg.git
-    cd vcpkg
-    ./bootstrap-vcpkg.sh
-    ./vcpkg integrate install
-    vcpkg install json-c
-
-The JSON-C port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
-
-Building on Unix with `git`, `gcc` and `autotools` <a name="buildunix"></a>
+Building on Unix with `git`, `gcc` and `cmake` <a name="buildunix"></a>
 --------------------------------------------------
 
 Home page for json-c: https://github.com/json-c/json-c/wiki
 
-### Prerequisites:
-
-See also the "Installing prerequisites" section below.
+### Prerequisites: <a name="installprereq"></a>
 
  - `gcc`, `clang`, or another C compiler
- - `libtool>=2.2.6b`
 
-If you're not using a release tarball, you'll also need:
+ - cmake>=2.8, >=3.16 recommended
 
- - `autoconf>=2.64` (`autoreconf`)
- - `automake>=1.13`
+To generate docs you'll also need:
+ - `doxygen>=1.8.13`
 
-Make sure you have a complete `libtool` install, including `libtoolize`.
+If you are on a relatively modern system, you'll likely be able to install
+the prerequisites using your OS's packaging system.
 
-To generate docs (e.g. as part of make distcheck) you'll also need:
- - `doxygen>=1.8.13`
+### Install using apt (e.g. Ubuntu 16.04.2 LTS)
+```sh
+sudo apt install git
+sudo apt install cmake
+sudo apt install doxygen  # optional
+sudo apt install valgrind # optional
+```
 
-### Build instructions:
+### Build instructions:  <a name="buildcmds"></a>
 
 `json-c` GitHub repo: https://github.com/json-c/json-c
 
 ```sh
 $ git clone https://github.com/json-c/json-c.git
-$ cd json-c
-$ sh autogen.sh
+$ mkdir json-c-build
+$ cd json-c-build
+$ cmake ../json-c   # See CMake section below for custom arguments
 ```
 
-followed by
+Note: it's also possible to put your build directory inside the json-c
+source directory, or even not use a separate build directory at all, but
+certain things might not work quite right (notably, `make distcheck`)
+
+Then:
 
 ```sh
-$ ./configure  # --enable-threading
 $ make
+$ make test
+$ make USE_VALGRIND=0 test   # optionally skip using valgrind
 $ make install
 ```
 
-To build and run the test programs:
-
-```sh
-$ make check
-$ make USE_VALGRIND=0 check   # optionally skip using valgrind
-```
 
-Install prerequisites <a name="installprereq"></a>
------------------------
+### Generating documentation with Doxygen:
 
-If you are on a relatively modern system, you'll likely be able to install
-the prerequisites using your OS's packaging system.
+The libray documentation can be generated directly from the source codes using Doxygen tool:
 
-### Install using apt (e.g. Ubuntu 16.04.2 LTS)
 ```sh
-sudo apt install git
-sudo apt install autoconf automake libtool
-sudo apt install valgrind # optional
+# in build directory
+make doc
+google-chrome doc/html/index.html
 ```
 
-Then start from the "git clone" command, above.
 
-### Manually install and build autoconf, automake and libtool
+CMake Options <a name="CMake"></a>
+--------------------
+
+The json-c library is built with [CMake](https://cmake.org/cmake-tutorial/),
+which can take a few options.
 
-For older OS's that don't have up-to-date versions of the packages will
-require a bit more work. For example, CentOS release 5.11, etc...
+Variable             | Type   | Description
+---------------------|--------|--------------
+CMAKE_INSTALL_PREFIX | String | The install location.
+CMAKE_BUILD_TYPE     | String | Defaults to "debug"
+BUILD_SHARED_LIBS    | Bool   | The default build generates a dynamic (dll/so) library.  Set this to OFF to create a static library instead.
+ENABLE_RDRAND        | Bool   | Enable RDRAND Hardware RNG Hash Seed
+ENABLE_THREADING     | Bool   | Enable partial threading support
+DISABLE_WERROR       | Bool   | Disable use of -Werror
+DISABLE_BSYMBOLIC    | Bool   | Disable use of -Bsymbolic-functions
+
+Pass these options as `-D` on CMake's command-line.
 
 ```sh
-curl -O http://ftp.gnu.org/gnu/autoconf/autoconf-2.69.tar.gz
-curl -O http://ftp.gnu.org/gnu/automake/automake-1.15.tar.gz
-curl -O http://ftp.gnu.org/gnu/libtool/libtool-2.2.6b.tar.gz
-
-tar xzf autoconf-2.69.tar.gz
-tar xzf automake-1.15.tar.gz
-tar xzf libtool-2.2.6b.tar.gz
-
-export PATH=${HOME}/ac_install/bin:$PATH
-
-(cd autoconf-2.69 && \
-  ./configure --prefix ${HOME}/ac_install && \
-  make && \
-  make install)
-
-(cd automake-1.15 && \
-  ./configure --prefix ${HOME}/ac_install && \
-  make && \
-  make install)
-
-(cd libtool-2.2.6b && \
-  ./configure --prefix ${HOME}/ac_install && \
-  make && \
-  make install)
+cmake -DBUILD_SHARED_LIBS=OFF ...
 ```
 
-
-Building with partial threading support <a name="buildthreaded"></a>
-----------------------------------------
+### Building with partial threading support
 
 Although json-c does not support fully multi-threaded access to
 object trees, it has some code to help make its use in threaded programs
@@ -142,49 +118,24 @@ json_object_get() and json_object_put().
 
 Since this may have a performance impact, of at least 3x slower
 according to https://stackoverflow.com/a/11609063, it is disabled by
-default.  You may turn it on by adjusting your configure command with:
-   --enable-threading
+default.  You may turn it on by adjusting your cmake command with:
+   -DENABLE_THREADING=ON
 
 Separately, the default hash function used for object field keys,
 lh_char_hash, uses a compare-and-swap operation to ensure the random
 seed is only generated once.  Because this is a one-time operation, it
 is always compiled in when the compare-and-swap operation is available.
 
-Building with CMake <a name="CMake"></a>
---------------------
 
-To use [CMake](https://cmake.org/cmake-tutorial/), build it like:
+### cmake-configure wrapper script
 
-```sh
-mkdir build
-cd build
-cmake ../
-make
-```
-
-CMake can take a few options.
-
-Variable             | Type   | Description
----------------------|--------|--------------
-CMAKE_INSTALL_PREFIX | String | The install location.
-BUILD_SHARED_LIBS    | Bool   | The default build generates a dynamic (dll/so) library.  Set this to OFF to create a static library instead.
-ENABLE_RDRAND        | Bool   | Enable RDRAND Hardware RNG Hash Seed
-ENABLE_THREADING     | Bool   | Enable partial threading support
-
-Pass these options as `-D` on CMake's command-line.
-
-```sh
-cmake -DBUILD_SHARED_LIBS=OFF ...
-```
-
-**In addition， you can also use cmake-configure: Wrapper around cmake to emulate useful options.**
-
-To use cmake-configure, build it like:
+For those familiar with the old autoconf/autogen.sh/configure method,
+there is a `cmake-configure` wrapper script to ease the transition to cmake.
 
 ```sh
 mkdir build
 cd build
-../cmake-configure --disable-werror
+../cmake-configure --prefix=/some/install/path
 make
 ```
 
@@ -200,7 +151,9 @@ cmake-configure can take a few options.
 | disable-Bsymbolic |  Avoid linking with -Bsymbolic-function |
 | disable-werror |  Avoid treating compiler warnings as fatal errors |
 
-Testing with cmake:
+
+Testing:  <a name="testing"></a>
+----------
 
 By default, if valgrind is available running tests uses it.
 That can slow the tests down considerably, so to disable it use:
@@ -208,11 +161,12 @@ That can slow the tests down considerably, so to disable it use:
 export USE_VALGRIND=0
 ```
 
-To run tests:
+To run tests a separate build directory is recommended:
 ```sh
 mkdir build-test
 cd build-test
-# VALGRIND=1 causes -DVALGRIND=1 to be included when building
+# VALGRIND=1 causes -DVALGRIND=1 to be passed when compiling code
+# which uses slightly slower, but valgrind-safe code.
 VALGRIND=1 cmake ..
 make
 
@@ -233,20 +187,20 @@ JSONC_TEST_TRACE=1 make test
 ```
 and check the log files again.
 
-To get doxygen documentation:
 
-The libray documentation can be generated directly from the source codes using Doxygen tool:
+Building on Unix and Windows with `vcpkg` <a name="buildvcpkg"></a>
+--------------------------------------------------
 
-```sh
-make doc
-google-chrome ../doc/html/index.html
-```
+You can download and install JSON-C using the [vcpkg](https://github.com/Microsoft/vcpkg/) dependency manager:
+
+    git clone https://github.com/Microsoft/vcpkg.git
+    cd vcpkg
+    ./bootstrap-vcpkg.sh
+    ./vcpkg integrate install
+    vcpkg install json-c
 
-To uninstall:
+The JSON-C port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please [create an issue or pull request](https://github.com/Microsoft/vcpkg) on the vcpkg repository.
 
-```sh
-make uninstall
-```
 
 Linking to `libjson-c` <a name="linking">
 ----------------------