This is a simple infrastructure to compile Arduino sketches on the Intel Galileo. Compiling sketches on the Intel Galileo is particular useful for clanton-full Linux installations based on eglibc (see e.g. http://www.malinov.com/Home/sergey-s-blog) where one installs a rich set of linux command on an SD card and boots the Galileo from this card.

Background: By default, the Arduino IDE builds sketches for ulibc, which are cross-compiled on a PC and downloaded via USB to the board. ulibc is very compact (necessary for the default tiny SPI-flash Linux), but it seems limited and is hard to debug (i run into problems with dynamic loading, ldd seems not available, etc.). Therefore, clanton-full distributions use usually eglibc. The downside of using eglibc is that sketches compiled with Arduino IDE and ulibc can't be executed in such an environment.

By compiling sketches directly on the Galileo under Linux, one can compile easily sketches with eglibc in a way natural for Linux developers while preserving the ease of sketches to interface with sensors and hardware gadgets.

One needs actually three steps to compile and execute sketches on the Intel Galileo:

1) Copy sources of libraries and Template for the sketch to the SD card
2) On Galileo, copy Template for the sketch and insert sketch
3) Compile via make and execute the sketch

PS: I've developed this package to ease teaching IoT appliances based on the Intel Galileo board.

1) Copy Sources of Libraries and Template for the Sketch to the SD Card

Copy libraries from the Arduino IDE for the Intel Galileo to the SD
card, which is used for booting the Galileo. The libraries are quite
small (total of less the 1.5 MB) without arduino-libs (which are optional)

Copy always the standard libraries (hardware/arduino); in case you
have user-installed libraries, copy these as well. Optionally,
the shipped Arduino examples for the Galileo can be copied (called
here arduino-libs).

Let us assume, the SD card has the label GALILEO, one can use the
following command under Mac OS X:

   ARDUINO=/Applications/Arduino.app
   VOLUME=/Volumes/GALILEO

   cp -r "${ARDUINO}/Contents/Resources/Java/hardware/intel/i586-uclibc" ${VOLUME}/i586-uclibc 
   cp -r ~/Documents/Arduino ${VOLUME}/arduino-local
   cp -r "${ARDUINO}/Contents/Resources/Java/libraries" ${VOLUME}/arduino-libs

Copy sketch template as well:

   cp -r sketch-template ${VOLUME}/sketch-template

For other operating systems you should find these libraries on the
listed places:

Linux:
 - standard libraries:  Arduino-1.5.3/hardware/arduino
 - user libraries:      ~/Sketchbook

Windows:
 - standard libraries:  Arduino-1.5.3/hardware/arduino
 - user libraries:      Documents/Arduino

2) On Galileo, copy Template for the Sketch and insert Sketch Source

Start the Galileo from the prepared SD card and log in (e.g. via
ssh). Copy the "VOLUME" content to some directory or use the
Volume directly. Assume, you want to compile the sketch
"Blink.ino". First copy the sketch-template to a new folder
used for your project (e.g. blink-sketch).

   VOLUME=/media/realroot

   cp -r ${VOLUME}/sketch-template ./blink-sketch
   cd ./blink-sketch

Edit in Makefile and set the variable SKETCH to the name of your sketch.
E.g.

   SKETCH=Blink

Copy the Blink sketch "Blink.ino" to this directory. You will find
the .ino file in the Arduino tree. Alternatively, simply edit a new
file named "Blink.ino" and paste the source from the Arduino IDE into
the editor. You might want to adjust some paths in the Makefile.

For larger projects, you might want to add user libraries. See
Makefile for an example.

3) Compile and Run the Sketch

To compile the sketch, run

   make

The Makefile will produce an executable named "sketch". One can run
it without arguments,

   ./sketch

Optionally one can provide ttys for "Serial", "Serial1" and
"Serial2" if these are connected:

   ./sketch tty0 tty1

For debugging during development it is the easiest to use
"fprintf(stderr, ....)" in your sketches since debugging
goes directly to the Linux console.