Error compiling libax25

[Carlos A Schneider]

Hello all:
I'm trying to compile libax25-0.0.7, but there are errors
during make.
Configure reports that can't locate file /sys/ioctl.h,
but it is there. So, I think that some libs are missing,
but I don't know which one.
I have glibc-2.1 installed, and the system is an 486DX2
running RH 6.0.
Could someone point me to the needed libs to compile it?

TIA