doc: add build instructions for libyang

These instructions are intended to be temporary until we have libyang
packages available for all supported platforms.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

doc/developer/building-frr-for-centos6.rst

@@ -115,6 +115,8 @@ Update rpm database & Install newer sphinx
    sudo yum update
    sudo yum install python27-sphinx
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-centos7.rst

@@ -24,6 +24,8 @@ Add packages:
       json-c-devel pam-devel bison flex pytest c-ares-devel \
       python-devel systemd-devel python-sphinx
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-debian8.rst

@@ -25,6 +25,8 @@ Install newer pytest (>3.0) from pip
 
     sudo pip install pytest
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-debian9.rst

@@ -12,6 +12,8 @@ Add packages:
       libreadline-dev texinfo libjson-c-dev pkg-config bison flex \
       python-pip libc-ares-dev python3-dev python-pytest python3-sphinx
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-fedora24.rst

@@ -17,6 +17,8 @@ Add packages:
       json-c-devel pam-devel pytest bison flex c-ares-devel \
       python3-devel python3-sphinx
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-freebsd10.rst

@@ -17,7 +17,7 @@ is first package install and asked)
 ::
 
     pkg install git autoconf automake libtool gmake gawk json-c pkgconf \
-        bison flex py27-pytest c-ares python3 py-sphinx
+        bison flex py27-pytest c-ares python3 py-sphinx libyang
 
 Make sure there is no /usr/bin/flex preinstalled (and use the newly
 installed in /usr/local/bin): (FreeBSD frequently provides a older flex

doc/developer/building-frr-for-freebsd11.rst

@@ -17,7 +17,7 @@ is first package install and asked)
 .. code-block:: shell
 
    pkg install git autoconf automake libtool gmake gawk json-c pkgconf \
-      bison flex py27-pytest c-ares python3 py36-sphinx texinfo
+      bison flex py27-pytest c-ares python3 py36-sphinx texinfo libyang
 
 Make sure there is no /usr/bin/flex preinstalled (and use the newly
 installed in /usr/local/bin): (FreeBSD frequently provides a older flex

doc/developer/building-frr-for-freebsd9.rst

@@ -40,6 +40,8 @@ compile)
     mv /usr/bin/clang /usr/bin/clang34
     ln -s /usr/local/bin/clang36 /usr/bin/clang
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-netbsd6.rst

@@ -40,6 +40,8 @@ Select default Python and py.test
     sudo ln -s /usr/pkg/bin/python2.7 /usr/bin/python
     sudo ln -s /usr/pkg/bin/py.test-2.7 /usr/bin/py.test
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-netbsd7.rst

@@ -31,6 +31,8 @@ Select default Python and py.test
     sudo ln -s /usr/pkg/bin/python2.7 /usr/bin/python
     sudo ln -s /usr/pkg/bin/py.test-2.7 /usr/bin/py.test
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-omnios.rst

@@ -86,6 +86,8 @@ Edit ``~/.profile`` and add the following default PATH:
 
     PATH=/usr/gnu/bin:/usr/bin:/usr/sbin:/sbin:/opt/csw/bin
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-openbsd6.rst

@@ -23,6 +23,8 @@ Select Python2.7 as default (required for pytest)
 
     ln -s /usr/local/bin/python2.7 /usr/local/bin/python
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-ubuntu1204.rst

@@ -64,6 +64,8 @@ Install pytest:
 
     pip install pytest
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-ubuntu1404.rst

@@ -18,6 +18,8 @@ Add packages:
        pkg-config libpam0g-dev libjson-c-dev bison flex python-pytest \
        libc-ares-dev python3-dev python3-sphinx install-info
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-ubuntu1604.rst

@@ -19,6 +19,8 @@ Add packages:
        libc-ares-dev python3-dev libsystemd-dev python-ipaddress \
        python3-sphinx install-info
 
+.. include:: building-libyang.rst
+
 Get FRR, compile it and install it (from Git)
 ---------------------------------------------
 

doc/developer/building-frr-for-ubuntu1804.rst

@@ -15,6 +15,8 @@ Required packages
       libc-ares-dev python3-dev libsystemd-dev python-ipaddress \
       python3-sphinx install-info
 
+.. include:: building-libyang.rst
+
 Optional packages
 ^^^^^^^^^^^^^^^^^
 

doc/developer/building-libyang.rst

@@ -0,0 +1,25 @@
+The libyang library can be installed from third-party packages available `here
+<https://ci1.netdef.org/browse/LIBYANG-YANGRELEASE/latestSuccessful/artifact>`_.
+
+Note: the libyang dev/devel packages need to be installed in addition
+to the libyang core package in order to build FRR successfully.
+
+Alternatively, libyang can be built and installed manually by following
+the steps below:
+
+.. code-block:: shell
+
+   git clone https://github.com/opensourcerouting/libyang
+   cd libyang
+   git checkout -b tmp origin/tmp
+   mkdir build; cd build
+   cmake -DENABLE_LYD_PRIV=ON ..
+   make
+   sudo make install
+
+When building libyang on CentOS 6, it's also necessary to pass the
+``-DENABLE_CACHE=OFF`` parameter to cmake.
+
+Note: please check the `libyang build requirements
+<https://github.com/CESNET/libyang/blob/master/README.md#build-requirements>`_
+first.