Ό gcc δέν βρίσκει την sqrt()

[Hlias]

Κάνω compile ένα πολύ απλό πρόγραμμα:

#include <stdio.h>
#include <math.h>
main()
{ double num;
        printf("Δώσε ένα θετικό αριθμό:");
        scanf("%lf", &num);



        if(num<0)
                printf("Λάθος είσοδος: Αριθμός αρνητικός\n");
        else
        printf("Η τετραγωνική ρίζα του %lf είναι %f\n", num , sqrt (num));
        exit(0);
}

Παίρνω στην εξοδό:

[hlias at papaya hlias]$ gcc test.c
/tmp/cce21dty.o(.text+0x63): In function `main':
: undefined reference to `sqrt'
collect2: ld returned 1 exit status

Αν τρεξω gcc -v test.c παίρνω:

Reading specs from /usr/lib/gcc-lib/i486-slackware-linux/3.2.3/specs
Configured with: ../gcc-3.2.3/configure --prefix=/usr --enable-shared
--enable-threads=posix --enable-__cxa_atexit --disable-checking
--with-gnu-ld --verbose --target=i486-slackware-linux
--host=i486-slackware-linux
Thread model: posix
gcc version 3.2.3
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/cc1 -lang-c -v -D__GNUC__=3
-D__GNUC_MINOR__=2 -D__GNUC_PATCHLEVEL__=3 -D__GXX_ABI_VERSION=102
-D__ELF__ -Dunix -D__gnu_linux__ -Dlinux -D__ELF__ -D__unix__
-D__gnu_linux__ -D__linux__ -D__unix -D__linux -Asystem=posix
-D__NO_INLINE__ -D__STDC_HOSTED__=1 -Acpu=i386 -Amachine=i386 -Di386
-D__i386 -D__i386__ -D__tune_i486__ test.c -quiet -dumpbase test.c
-version -o /tmp/cc391aIr.s
GNU CPP version 3.2.3 (cpplib) (i386 Linux/ELF)
GNU C version 3.2.3 (i486-slackware-linux)
         compiled by GNU C version 3.2.3.
ignoring nonexistent directory "/usr/i486-slackware-linux/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/local/include
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/include
/usr/include
End of search list.
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../../../i486-slackware-linux/bin/as 



-V -Qy -o /tmp/ccsOS4zL.o /tmp/cc391aIr.s
GNU assembler version 2.14.90.0.6 (i486-slackware-linux) using BFD
version 2.14.90.0.6 20030820
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/collect2 --eh-frame-hdr -m
elf_i386 -dynamic-linker /lib/ld-linux.so.2
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../../crt1.o
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../../crti.o
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/crtbegin.o
-L/usr/lib/gcc-lib/i486-slackware-linux/3.2.3
-L/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../../../i486-slackware-linux/lib 



-L/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../.. /tmp/ccsOS4zL.o
-lgcc -lgcc_eh -lc -lgcc -lgcc_eh
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/crtend.o
/usr/lib/gcc-lib/i486-slackware-linux/3.2.3/../../../crtn.o
/tmp/ccsOS4zL.o(.text+0x63): In function `main':
: undefined reference to `sqrt'
collect2: ld returned 1 exit status

Ποιό είναι το λάθος μου;;