I do not know a mobile platform where its SDK are reccomending using pure C anymore. Last that I knew of was the old Palm platform.
But you can write C/C++ with QT as GUI library for Maemo, MeeGo and possibly other Nokia devices. QT are object oriented, so its not procedural as you want.
I know of 1 platform where pure C is possible. That's the windows mobile version <6.5 using win32 api. But this is not a thing I personally recommend doing since C#.NET makes it easier to develop applications for that platform. I also think that pure C combined with XML/CSS using the WebOS PDK is possible but I might be wrong here.
If you have a wish to write for mobile devices using your knowledge in C then i would rather recommend to use languages like C++ and Objective-C where you also can write C and use C libraries.
A list of mobile devices and the programming languages used to develop applications for them:
Symbian - C/C++
iOS - Objective-C
Android - Java
Windows Mobile - C/C++/.NET
WebOS - C/C++