cannot find -lm

[Eric Fisher]

Hi,
When I run the test suite on my port, there are many many failures
with the error like this,

ld: cannot find -lm
collect2: ld returned 1 exit status

I'm not sure whether it is the libm(math library), or it is of glibc.
But I guess it is a builtin library of gcc and has nothing to do with
math. Is it right? How can I get it?

Thanks.
Eric.