Create README_BUILD.md

pre requests from some distribution maintainers, add a small readme for build instructions.

Signed-off-by: Robin Getz [email protected]

README_BUILD.md

@@ -0,0 +1,66 @@
+# Build instructions for libiio
+
+## Install Prerequisites/Dependancies
+
+Basic system setup
+```shell
+analog@precision:~$ sudo apt-get update
+analog@precision:~$ sudo apt-get install build-essential
+```
+Install Prerequisites
+```shell
+analog@precision:~$ sudo apt-get install libxml2-dev bison flex libcdk5-dev cmake
+```
+Install Backends
+```shell
+analog@precision:~$ sudo apt-get install libaio-dev libusb-1.0-0-dev libserialport-dev libavahi-client-dev
+```
+Install to build doc
+```shell
+sudo apt-get install doxygen graphviz
+```
+## Clone
+```shell
+analog@precision:~$ git clone https://github.com/analogdevicesinc/libiio.git
+analog@precision:~$ cd libiio
+```
+
+## Configure & Build
+
+when configuring libiio with cmake, there are a few optional settings that you can use to control the build.
+
+Cmake Options       | Default | Description                                    |
+------------------- | ------- | ---------------------------------------------- |
+`CSHARP_BINDINGS`   | OFF | Install C# bindings                                |
+`MATLAB_BINDINGS`   | OFF | Install MATLAB bindings                            |
+`PYTHON_BINDINGS`   | OFF | Install PYTHON bindings                            |
+`WITH_DOC`          | OFF | Generate documentation with Doxygen                |
+`WITH_MAN`          | OFF | Generate and install man pages                     |
+`WITH_TESTS`        |  ON | Build the test programs                            |
+`WITH_LOCAL_CONFIG` | OFF | Read local context attributes from /etc/libiio.ini |
+`ENABLE_PACKAGING`  | OFF | Create .deb/.rpm/.tar.gz via 'make package'        |
+`INSTALL_UDEV_RULE` |  ON | Install a udev rule for detection of USB devices   |
+
+Which backends the library supports is dependant on the build system, but can be overridden.
+(If cmake finds libusb, it will use it, unless turned off manually)
+
+Cmake Options          | Depends on    | Description                     |
+---------------------- | ------------- | ------------------------------- |
+`WITH_XML_BACKEND`     | libxml2       | Enable the XML backend          |
+`WITH_USB_BACKEND`     | libusb        | Enable the libusb backend       |
+`WITH_SERIAL_BACKEND`  | libserialport | Enable the Serial backend       |
+`WITH_NETWORK_BACKEND` |               | Supports TCP/IP                 |
+`WITH_LOCAL_BACKEND`   | Linux         | Enables local support with iiod |
+
+
+```shell
+analog@precision:~/libiio$ mkdir build
+analog@precision:~/libiio/build$ cd build
+analog@precision:~/libiio/build$ cmake ../
+analog@precision:~/libiio/build$ make -j$(nproc)
+```
+
+## Install
+```shell
+analog@precision:~/libiio/build$ sudo make install
+```