cc/gcc: with static ppl, correctly link with libm

On some Fedora boxen (at least FC13), it is also required
to link with libm when static ppl is used.
(transplanted from bcd33fce4db9c18223b59ecdc96f10bf6dd574de)

 --- binutils/ld/ldmain.c

 +++ binutils/ld/ldmain.c

 @@ -293,2 +293,3 @@ main (int argc, char **argv)

    link_info.combreloc = TRUE;

 +  link_info.relro = TRUE;

    link_info.strip_discarded = TRUE;