madplay crosscompile

Hello~ This is my first post on this website. ^__^;

I use Ubuntu as a host, and the target board is a kind of MIPS processor (specific information shown below).

The target's info
system type : BCM97xxx Settop Platform
processor : 0
cpu model : Brcm7401 V0.0
cpu MHz : 295.93
BogoMIPS : 295.93 ( udelay_val : 147968 HZ = 1000)
...
..

In order to play "madplay" (which is a kind of mp3 decoder) on the target,I am using "mipsel-uclibc-gcc" compiler.

In the compile process, I need to type this kind of shell(BASH)command.

"CC= CFLAGS= LIBS= ./configure"

I think "CC=" is "mipsel-uclibc-gcc"
However, I don't know the values of "CFLAGS=" and "LIBS="
I understand the conceptual meanings of the two values (CFLAGS and LIBS)

But, how do I know the values? or
Where can I found the related information to find the values?

Smart babies, pleas answer me!! ^__^;