Somebody please help me to develop apps with IUP Portable User Interface toolkit with C in Linux (Ubuntu 12.04_amd64(actually i am using elementary :P) with Linux 3.2.0-51-generic to be more specific)[by the way i know nothing about iup - i came across it just 24 hrs ago and failed to run even the helloworld example :(]
There are many reasons an application would fail to build. Without knowing what exactly happen makes it more difficult to help.
If you contact the IUP team at iup@tecgraf.puc-rio.br or post a message at the IUP mailing list I would be glad to assist you.
Best, Antonio Scuri