I'm using the latest ICC for the Atom platform. There doesn't seem to be a libm.so library under /opt/intel/atom/Compilers/1.11/072/lib/ia32/ , yet my linker seems to want to link against -lm. Also, I tried to link against -limf, which to my knowledge is the Intel equivalent to -lm. That doesn't seem to appease the linker though.
Yes, the glibc libm is the last resort for linking in all cases. The library search paths inherited from g++ are used to find it. You could turn on -# in order to see more detail on the link steps. The substitution of libimf functions to preempt glibc presumably is controlled more by use of the associated include file than by minor changes in the link order.