I found this thread on the clanlib forums, I didn't read very careful, but it seems as if they have a GL1 target that uses only requires OpenGL 1.3, and that it could be used for OpenGL ES 1.1.
Quotes from the developer rombust:
Can you post the patch onto the forum (zip it)
I have created a clanGLES1 target for support for clanGL < 2.0 that should support OpenGL ES 1.1 (and OpenGL 1.x)
It would be helpful to incorporate your patch.