ld: not warning undefined symbols

I'm not using "elf2flt", because I'm using the example I found in the documentation... In the Makefile, I wrote:

TSTPRG = myprog.exe
all: $(TSTPROG)

When I do "make all", it compiles my program and generates an .exe file. I've seen that it uses elf2flt

nios2-linux-uclibc-gcc -nostdinc -O2 -I/home/indes/opo/kernel/uClinux-dist-test/uClibc/include -I/opt/nios2/lib/gcc/nios2-linux-uclibc/3.4.6/include -fno-optimize-sibling-calls -mhw-mul -mhw-mulx -Wall -c -o myprog.o myprog.c
nios2-linux-uclibc-gcc -msys-crt0=/home/uClibc/lib/crt0.o -r -d -L/home/uClinux-dist-test/uClibc/lib -o myprog.bin myprog.o /opt/nios2/lib/gcc/nios2-linux-uclibc/3.4.6/../../../../nios2-linux-uclibc/lib/libm.a /opt/nios2/lib/gcc/nios2-linux-uclibc/3.4.6/libgcc.a /home/indes/opo/kernel/uClinux-dist-test/uClibc/lib/libc.a --no-undefined
nios2-linux-uclibc-ld -T /opt/nios2/scripts/elf2flt.ld -Ur -o myprog.elf myprog.bin
/opt/nios2/bin/elf2flt  -o myprog.flt myprog.elf
cp -f myprog.flt myprog.exe
rm myprog.elf myprog.flt myprog.bin myprog.o

The strange thing is that it shows the same if I include the references to the libraries it needs, or if I don't include them. It doesn't warn about anything...

any idea?

aLeX